diff --git a/PKG-INFO b/PKG-INFO
index 22582bf1..36bc2772 100644
--- a/PKG-INFO
+++ b/PKG-INFO
@@ -1,152 +1,152 @@
 Metadata-Version: 2.1
 Name: swh.storage
-Version: 0.0.138
+Version: 0.0.139
 Summary: Software Heritage storage manager
 Home-page: https://forge.softwareheritage.org/diffusion/DSTO/
 Author: Software Heritage developers
 Author-email: swh-devel@inria.fr
 License: UNKNOWN
 Project-URL: Source, https://forge.softwareheritage.org/source/swh-storage
 Project-URL: Funding, https://www.softwareheritage.org/donate
 Project-URL: Bug Reports, https://forge.softwareheritage.org/maniphest
 Description: swh-storage
         ===========
         
         Abstraction layer over the archive, allowing to access all stored source code
         artifacts as well as their metadata.
         
         See the
         [documentation](https://docs.softwareheritage.org/devel/swh-storage/index.html)
         for more details.
         
         Tests
         -----
         
         Python tests for this module include tests that cannot be run without a local
         Postgres database. You are not obliged to run those tests though:
         
         - `make test`:      will run all tests
         - `make test-nodb`: will run only tests that do not need a local DB
         - `make test-db`:   will run only tests that do need a local DB
         
         If you do want to run DB-related tests, you should ensure you have access zith
         sufficient privileges to a Postgresql database.
         
         ### Using your system database
         
         You need to ensure that your user is authorized to create and drop DBs, and in
         particular DBs named "softwareheritage-test" and "softwareheritage-dev"
         
         Note: the testdata repository (swh-storage-testdata) is not required any more.
         
         ### Using pifpaf
         
         [pifpaf](https://github.com/jd/pifpaf) is a suite of fixtures and a
         command-line tool that allows to start and stop daemons for a quick throw-away
         usage.
         
         It can be used to run tests that need a Postgres database without any other
         configuration reauired nor the need to have special access to a running
         database:
         
         ```bash
         
         $ pifpaf run postgresql make test-db
         [snip]
         ----------------------------------------------------------------------
         Ran 124 tests in 56.203s
         
         OK
         ```
         
         Note that pifpaf is not yet available as a Debian package, so you may have to
         install it in a venv.
         
         
         Development
         -----------
         
         A test server could locally be running for tests.
         
         ### Sample configuration
         
         In either /etc/softwareheritage/storage/storage.yml,
         ~/.config/swh/storage.yml or ~/.swh/storage.yml:
         
         ```
         storage:
           cls: local
           args:
             db: "dbname=softwareheritage-dev user=<user>"
             objstorage:
               cls: pathslicing
               args:
                 root: /home/storage/swh-storage/
                 slicing: 0:2/2:4/4:6
         ```
         
         which means, this uses:
         
         - a local storage instance whose db connection is to
           softwareheritage-dev local instance
         
         - the objstorage uses a local objstorage instance whose:
         
           - root path is /home/storage/swh-storage
         
           - slicing scheme is 0:2/2:4/4:6. This means that the identifier of
             the content (sha1) which will be stored on disk at first level
             with the first 2 hex characters, the second level with the next 2
             hex characters and the third level with the next 2 hex
             characters. And finally the complete hash file holding the raw
             content. For example: 00062f8bd330715c4f819373653d97b3cd34394c
             will be stored at 00/06/2f/00062f8bd330715c4f819373653d97b3cd34394c
         
         Note that the 'root' path should exist on disk.
         
         
         ### Run server
         
         Command:
         ```
         python3 -m swh.storage.api.server ~/.config/swh/storage.yml
         ```
         
         This runs a local swh-storage api at 5002 port.
         
         
         ### And then what?
         
         In your upper layer (loader-git, loader-svn, etc...), you can define a
         remote storage with this snippet of yaml configuration.
         
         ```
         storage:
           cls: remote
           args:
             url: http://localhost:5002/
         ```
         
         You could directly define a local storage with the following snippet:
         
         ```
         storage:
           cls: local
           args:
             db: service=swh-dev
             objstorage:
               cls: pathslicing
               args:
                 root: /home/storage/swh-storage/
                 slicing: 0:2/2:4/4:6
         ```
         
 Platform: UNKNOWN
 Classifier: Programming Language :: Python :: 3
 Classifier: Intended Audience :: Developers
 Classifier: License :: OSI Approved :: GNU General Public License v3 (GPLv3)
 Classifier: Operating System :: OS Independent
 Classifier: Development Status :: 5 - Production/Stable
 Description-Content-Type: text/markdown
 Provides-Extra: schemata
 Provides-Extra: testing
diff --git a/swh.storage.egg-info/PKG-INFO b/swh.storage.egg-info/PKG-INFO
index 22582bf1..36bc2772 100644
--- a/swh.storage.egg-info/PKG-INFO
+++ b/swh.storage.egg-info/PKG-INFO
@@ -1,152 +1,152 @@
 Metadata-Version: 2.1
 Name: swh.storage
-Version: 0.0.138
+Version: 0.0.139
 Summary: Software Heritage storage manager
 Home-page: https://forge.softwareheritage.org/diffusion/DSTO/
 Author: Software Heritage developers
 Author-email: swh-devel@inria.fr
 License: UNKNOWN
 Project-URL: Source, https://forge.softwareheritage.org/source/swh-storage
 Project-URL: Funding, https://www.softwareheritage.org/donate
 Project-URL: Bug Reports, https://forge.softwareheritage.org/maniphest
 Description: swh-storage
         ===========
         
         Abstraction layer over the archive, allowing to access all stored source code
         artifacts as well as their metadata.
         
         See the
         [documentation](https://docs.softwareheritage.org/devel/swh-storage/index.html)
         for more details.
         
         Tests
         -----
         
         Python tests for this module include tests that cannot be run without a local
         Postgres database. You are not obliged to run those tests though:
         
         - `make test`:      will run all tests
         - `make test-nodb`: will run only tests that do not need a local DB
         - `make test-db`:   will run only tests that do need a local DB
         
         If you do want to run DB-related tests, you should ensure you have access zith
         sufficient privileges to a Postgresql database.
         
         ### Using your system database
         
         You need to ensure that your user is authorized to create and drop DBs, and in
         particular DBs named "softwareheritage-test" and "softwareheritage-dev"
         
         Note: the testdata repository (swh-storage-testdata) is not required any more.
         
         ### Using pifpaf
         
         [pifpaf](https://github.com/jd/pifpaf) is a suite of fixtures and a
         command-line tool that allows to start and stop daemons for a quick throw-away
         usage.
         
         It can be used to run tests that need a Postgres database without any other
         configuration reauired nor the need to have special access to a running
         database:
         
         ```bash
         
         $ pifpaf run postgresql make test-db
         [snip]
         ----------------------------------------------------------------------
         Ran 124 tests in 56.203s
         
         OK
         ```
         
         Note that pifpaf is not yet available as a Debian package, so you may have to
         install it in a venv.
         
         
         Development
         -----------
         
         A test server could locally be running for tests.
         
         ### Sample configuration
         
         In either /etc/softwareheritage/storage/storage.yml,
         ~/.config/swh/storage.yml or ~/.swh/storage.yml:
         
         ```
         storage:
           cls: local
           args:
             db: "dbname=softwareheritage-dev user=<user>"
             objstorage:
               cls: pathslicing
               args:
                 root: /home/storage/swh-storage/
                 slicing: 0:2/2:4/4:6
         ```
         
         which means, this uses:
         
         - a local storage instance whose db connection is to
           softwareheritage-dev local instance
         
         - the objstorage uses a local objstorage instance whose:
         
           - root path is /home/storage/swh-storage
         
           - slicing scheme is 0:2/2:4/4:6. This means that the identifier of
             the content (sha1) which will be stored on disk at first level
             with the first 2 hex characters, the second level with the next 2
             hex characters and the third level with the next 2 hex
             characters. And finally the complete hash file holding the raw
             content. For example: 00062f8bd330715c4f819373653d97b3cd34394c
             will be stored at 00/06/2f/00062f8bd330715c4f819373653d97b3cd34394c
         
         Note that the 'root' path should exist on disk.
         
         
         ### Run server
         
         Command:
         ```
         python3 -m swh.storage.api.server ~/.config/swh/storage.yml
         ```
         
         This runs a local swh-storage api at 5002 port.
         
         
         ### And then what?
         
         In your upper layer (loader-git, loader-svn, etc...), you can define a
         remote storage with this snippet of yaml configuration.
         
         ```
         storage:
           cls: remote
           args:
             url: http://localhost:5002/
         ```
         
         You could directly define a local storage with the following snippet:
         
         ```
         storage:
           cls: local
           args:
             db: service=swh-dev
             objstorage:
               cls: pathslicing
               args:
                 root: /home/storage/swh-storage/
                 slicing: 0:2/2:4/4:6
         ```
         
 Platform: UNKNOWN
 Classifier: Programming Language :: Python :: 3
 Classifier: Intended Audience :: Developers
 Classifier: License :: OSI Approved :: GNU General Public License v3 (GPLv3)
 Classifier: Operating System :: OS Independent
 Classifier: Development Status :: 5 - Production/Stable
 Description-Content-Type: text/markdown
 Provides-Extra: schemata
 Provides-Extra: testing
diff --git a/swh/storage/algos/revisions_walker.py b/swh/storage/algos/revisions_walker.py
index 9b683f83..455b7ab7 100644
--- a/swh/storage/algos/revisions_walker.py
+++ b/swh/storage/algos/revisions_walker.py
@@ -1,513 +1,520 @@
 # Copyright (C) 2018  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 import heapq
 
 from abc import ABCMeta, abstractmethod
 from collections import deque
 
 _revs_walker_classes = {}
 
 
 class _RevisionsWalkerMetaClass(ABCMeta):
     def __new__(cls, clsname, bases, attrs):
         newclass = super().__new__(cls, clsname, bases, attrs)
         if 'rw_type' in attrs:
             _revs_walker_classes[attrs['rw_type']] = newclass
         return newclass
 
 
 class RevisionsWalker(metaclass=_RevisionsWalkerMetaClass):
     """
     Abstract base class encapsulating the logic to walk across
     a revisions history starting from a given one.
 
     It defines an iterator returning the revisions according
     to a specific ordering implemented in derived classes.
 
     The iteration step performs the following operations:
 
         1) Check if the iteration is finished by calling method
            :meth:`is_finished` and raises :exc:`StopIteration` if it
            it is the case
 
         2) Get the next unseen revision by calling method
            :meth:`get_next_rev_id`
 
         3) Process parents of that revision by calling method
            :meth:`process_parent_revs` for the next iteration
            steps
 
         4) Check if the revision should be returned by calling
            method :meth:`should_return` and returns it if
            it is the case
 
     In order to easily instantiate a specific type of revisions
     walker, it is recommended to use the factory function
     :func:`get_revisions_walker`.
 
     Args:
         storage (swh.storage.storage.Storage): instance of swh storage
             (either local or remote)
         rev_start (bytes): a revision identifier
         max_revs (Optional[int]): maximum number of revisions to return
         state (Optional[dict]): previous state of that revisions walker
     """
 
     def __init__(self, storage, rev_start, max_revs=None, state=None):
         self._revs_to_visit = []
         self._done = set()
         self._revs = {}
         self._last_rev = None
         self._num_revs = 0
         self._max_revs = max_revs
         if state:
             self._revs_to_visit = state['revs_to_visit']
             self._done = state['done']
             self._last_rev = state['last_rev']
             self._num_revs = state['num_revs']
         self.storage = storage
         self.process_rev(rev_start)
 
     @abstractmethod
     def process_rev(self, rev_id):
         """
         Abstract method whose purpose is to process a newly visited
         revision during the walk.
         Derived classes must implement it according to the desired
         method to walk across the revisions history (for instance
         through a dfs on the revisions DAG).
 
         Args:
             rev_id (bytes): the newly visited revision identifier
         """
         pass
 
     @abstractmethod
     def get_next_rev_id(self):
         """
         Abstract method whose purpose is to return the next revision
         during the iteration.
         Derived classes must implement it according to the desired
         method to walk across the revisions history.
 
         Returns:
             dict: A dict describing a revision as returned by
             :meth:`swh.storage.storage.Storage.revision_get`
         """
         pass
 
     def process_parent_revs(self, rev):
         """
         Process the parents of a revision when it is iterated.
         The default implementation simply calls :meth:`process_rev`
         for each parent revision in the order they are declared.
 
         Args:
             rev (dict): A dict describing a revision as returned by
                 :meth:`swh.storage.storage.Storage.revision_get`
         """
         for parent_id in rev['parents']:
             self.process_rev(parent_id)
 
     def should_return(self, rev):
         """
         Filter out a revision to return if needed.
         Default implementation returns all iterated revisions.
 
         Args:
             rev (dict): A dict describing a revision as returned by
                 :meth:`swh.storage.storage.Storage.revision_get`
 
         Returns:
             bool: Whether to return the revision in the iteration
         """
         return True
 
     def is_finished(self):
         """
         Determine if the iteration is finished.
         This method is called at the beginning of each iteration loop.
 
         Returns:
             bool: Whether the iteration is finished
         """
         if self._max_revs is not None and self._num_revs >= self._max_revs:
             return True
         if not self._revs_to_visit:
             return True
         return False
 
     def _get_rev(self, rev_id):
-        rev = self._revs.get(rev_id, None)
-        if not rev:
+        rev = self._revs.get(rev_id)
+        if rev is None:
             # cache some revisions in advance to avoid sending too much
             # requests to storage and thus speedup the revisions walk
             for rev in self.storage.revision_log([rev_id], limit=100):
+                # revision data is missing, returned history will be truncated
+                if rev is None:
+                    continue
                 self._revs[rev['id']] = rev
-        return self._revs[rev_id]
+        return self._revs.get(rev_id)
 
     def export_state(self):
         """
         Export the internal state of that revision walker to a dict.
         Its purpose is to continue the iteration in a pagination context.
 
         Returns:
             dict: A dict containing the internal state of that revisions walker
         """
         return {
             'revs_to_visit': self._revs_to_visit,
             'done': self._done,
             'last_rev': self._last_rev,
             'num_revs': self._num_revs
         }
 
     def __next__(self):
         if self.is_finished():
             raise StopIteration
         while self._revs_to_visit:
             rev_id = self.get_next_rev_id()
             if rev_id in self._done:
                 continue
             self._done.add(rev_id)
             rev = self._get_rev(rev_id)
+            # revision data is missing, returned history will be truncated
+            if rev is None:
+                continue
             self.process_parent_revs(rev)
             if self.should_return(rev):
                 self._num_revs += 1
                 self._last_rev = rev
                 return rev
         raise StopIteration
 
     def __iter__(self):
         return self
 
 
 class CommitterDateRevisionsWalker(RevisionsWalker):
     """
     Revisions walker that returns revisions in reverse chronological
     order according to committer date (same behaviour as ``git log``)
     """
 
     rw_type = 'committer_date'
 
     def process_rev(self, rev_id):
         """
         Add the revision to a priority queue according to the committer date.
 
         Args:
             rev_id (bytes): the newly visited revision identifier
         """
         if rev_id not in self._done:
             rev = self._get_rev(rev_id)
-            commit_time = rev['committer_date']['timestamp']['seconds']
-            heapq.heappush(self._revs_to_visit, (-commit_time, rev_id))
+            if rev is not None:
+                commit_time = rev['committer_date']['timestamp']['seconds']
+                heapq.heappush(self._revs_to_visit, (-commit_time, rev_id))
 
     def get_next_rev_id(self):
         """
         Return the smallest revision from the priority queue, i.e.
         the one with highest committer date.
 
         Returns:
             dict: A dict describing a revision as returned by
             :meth:`swh.storage.storage.Storage.revision_get`
         """
         _, rev_id = heapq.heappop(self._revs_to_visit)
         return rev_id
 
 
 class BFSRevisionsWalker(RevisionsWalker):
     """
     Revisions walker that returns revisions in the same order
     as when performing a breadth-first search on the revisions
     DAG.
     """
 
     rw_type = 'bfs'
 
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
         self._revs_to_visit = deque(self._revs_to_visit)
 
     def process_rev(self, rev_id):
         """
         Append the revision to a queue.
 
         Args:
             rev_id (bytes): the newly visited revision identifier
         """
         if rev_id not in self._done:
             self._revs_to_visit.append(rev_id)
 
     def get_next_rev_id(self):
         """
         Return the next revision from the queue.
 
         Returns:
             dict: A dict describing a revision as returned by
             :meth:`swh.storage.storage.Storage.revision_get`
         """
         return self._revs_to_visit.popleft()
 
 
 class DFSPostRevisionsWalker(RevisionsWalker):
     """
     Revisions walker that returns revisions in the same order
     as when performing a depth-first search in post-order on the
     revisions DAG (i.e. after visiting a merge commit,
     the merged commit will be visited before the base it was
     merged on).
     """
 
     rw_type = 'dfs_post'
 
     def process_rev(self, rev_id):
         """
         Append the revision to a stack.
 
         Args:
             rev_id (bytes): the newly visited revision identifier
         """
         if rev_id not in self._done:
             self._revs_to_visit.append(rev_id)
 
     def get_next_rev_id(self):
         """
         Return the next revision from the stack.
 
         Returns:
             dict: A dict describing a revision as returned by
             :meth:`swh.storage.storage.Storage.revision_get`
         """
         return self._revs_to_visit.pop()
 
 
 class DFSRevisionsWalker(DFSPostRevisionsWalker):
     """
     Revisions walker that returns revisions in the same order
     as when performing a depth-first search in pre-order on the
     revisions DAG (i.e. after visiting a merge commit,
     the base commit it was merged on will be visited before
     the merged commit).
     """
 
     rw_type = 'dfs'
 
     def process_parent_revs(self, rev):
         """
         Process the parents of a revision when it is iterated in
         the reversed order they are declared.
 
         Args:
             rev (dict): A dict describing a revision as returned by
                 :meth:`swh.storage.storage.Storage.revision_get`
         """
         for parent_id in reversed(rev['parents']):
             self.process_rev(parent_id)
 
 
 class PathRevisionsWalker(CommitterDateRevisionsWalker):
     """
     Revisions walker that returns revisions where a specific
     path in the source tree has been modified, in other terms
     it allows to get the history for a specific file or directory.
 
     It has a behaviour similar to what ``git log`` offers by default,
     meaning the returned history is simplified in order to only
     show relevant revisions (see the `History Simplification
     <https://git-scm.com/docs/git-log#_history_simplification>`_
     section of the associated manual for more details).
 
     Please note that to avoid walking the entire history, the iteration
     will stop once a revision where the path has been added is found.
 
     .. warning:: Due to client-side implementation, performances
         are not optimal when the total numbers of revisions to walk
         is large. This should only be used when the total number of
         revisions does not exceed a couple of thousands.
 
     Args:
         storage (swh.storage.storage.Storage): instance of swh storage
             (either local or remote)
         rev_start (bytes): a revision identifier
         path (str): the path in the source tree to retrieve the history
         max_revs (Optional[int]): maximum number of revisions to return
         state (Optional[dict]): previous state of that revisions walker
     """
 
     rw_type = 'path'
 
     def __init__(self, storage, rev_start, path, **kwargs):
         super().__init__(storage, rev_start, **kwargs)
         paths = path.strip('/').split('/')
         self._path = list(map(lambda p: p.encode('utf-8'), paths))
         self._rev_dir_path = {}
 
     def _get_path_id(self, rev_id):
         """
         Return the path checksum identifier in the source tree of the
         provided revision. If the path corresponds to a directory, the
         value computed by :func:`swh.model.identifiers.directory_identifier`
         will be returned. If the path corresponds to a file, its sha1
         checksum will be returned.
 
         Args:
             rev_id (bytes): a revision identifier
 
         Returns:
             bytes: the path identifier
         """
 
         rev = self._get_rev(rev_id)
 
         rev_dir_id = rev['directory']
 
         if rev_dir_id not in self._rev_dir_path:
             try:
                 dir_info = \
                     self.storage.directory_entry_get_by_path(rev_dir_id,
                                                              self._path)
                 self._rev_dir_path[rev_dir_id] = dir_info['target']
             except Exception:
                 self._rev_dir_path[rev_dir_id] = None
 
         return self._rev_dir_path[rev_dir_id]
 
     def is_finished(self):
         """
         Check if the revisions iteration is finished.
         This checks for the specified path's existence in the last
         returned revision's parents' source trees.
         If not, the iteration is considered finished.
 
         Returns:
             bool: Whether to return the revision in the iteration
         """
         if self._path and self._last_rev:
             last_rev_parents = self._last_rev['parents']
             last_rev_parents_path_ids = [self._get_path_id(p_rev)
                                          for p_rev in last_rev_parents]
             no_path = all([path_id is None
                            for path_id in last_rev_parents_path_ids])
             if no_path:
                 return True
         return super().is_finished()
 
     def process_parent_revs(self, rev):
         """
         Process parents when a new revision is iterated.
         It enables to get a simplified revisions history in the same
         manner as ``git log``. When a revision has multiple parents,
         the following process is applied. If the revision was a merge,
         and has the same path identifier to one parent, follow only that
         parent (even if there are several parents with the same path
         identifier, follow only one of them.) Otherwise, follow all parents.
 
         Args:
             rev (dict): A dict describing a revision as returned by
                 :meth:`swh.storage.storage.Storage.revision_get`
         """
         rev_path_id = self._get_path_id(rev['id'])
 
         if rev_path_id:
             if len(rev['parents']) == 1:
                 self.process_rev(rev['parents'][0])
             else:
                 parent_rev_path_ids = [self._get_path_id(p_rev)
                                        for p_rev in rev['parents']]
                 different_trees = all([path_id != rev_path_id
                                        for path_id in parent_rev_path_ids])
                 for i, p_rev in enumerate(rev['parents']):
                     if different_trees or \
                             parent_rev_path_ids[i] == rev_path_id:
                         self.process_rev(p_rev)
                         if not different_trees:
                             break
         else:
             super().process_parent_revs(rev)
 
     def should_return(self, rev):
         """
         Check if a revision should be returned when iterating.
         It verifies that the specified path has been modified
         by the revision but also that all parents have a path
         identifier different from the revision one in order
         to get a simplified history.
 
         Args:
             rev (dict): A dict describing a revision as returned by
                 :meth:`swh.storage.storage.Storage.revision_get`
 
         Returns:
             bool: Whether to return the revision in the iteration
         """
         rev_path_id = self._get_path_id(rev['id'])
 
         if not rev['parents']:
             return rev_path_id is not None
 
         parent_rev_path_ids = [self._get_path_id(p_rev)
                                for p_rev in rev['parents']]
         different_trees = all([path_id != rev_path_id
                                for path_id in parent_rev_path_ids])
 
         if rev_path_id != parent_rev_path_ids[0] and different_trees:
             return True
 
         return False
 
 
 def get_revisions_walker(rev_walker_type, *args, **kwargs):
     """
     Instantiate a revisions walker of a given type.
 
     The following code snippet demonstrates how to use a revisions
     walker for processing a whole revisions history::
 
         from swh.storage import get_storage
 
         storage = get_storage(...)
 
         revs_walker = get_revisions_walker('committer_date', storage, rev_id)
         for rev in revs_walker:
             # process revision rev
 
     It is also possible to walk a revisions history in a paginated
     way as illustrated below::
 
         def get_revs_history_page(rw_type, storage, rev_id, page_num,
                                   page_size, rw_state):
             max_revs = (page_num + 1) * page_size
             revs_walker = get_revisions_walker(rw_type, storage, rev_id,
                                                max_revs=max_revs,
                                                state=rw_state)
             revs = list(revs_walker)
             rw_state = revs_walker.export_state()
             return revs
 
         rev_start = ...
         per_page = 50
         rw_state = {}
 
         for page in range(0, 10):
             revs_page = get_revs_history_page('dfs', storage, rev_start, page,
                                               per_page, rw_state)
             # process revisions page
 
 
     Args:
         rev_walker_type (str): the type of revisions walker to return,
             possible values are: *committer_date*, *dfs*, *dfs_post*,
             *bfs* and *path*
         args (list): position arguments to pass to the revisions walker
             constructor
         kwargs (dict): keyword arguments to pass to the revisions walker
             constructor
 
     """
     if rev_walker_type not in _revs_walker_classes:
         raise Exception('No revisions walker found for type "%s"'
                         % rev_walker_type)
     revs_walker_class = _revs_walker_classes[rev_walker_type]
     return revs_walker_class(*args, **kwargs)
diff --git a/swh/storage/api/server.py b/swh/storage/api/server.py
index c54934a8..856e97f1 100644
--- a/swh/storage/api/server.py
+++ b/swh/storage/api/server.py
@@ -1,597 +1,600 @@
 # Copyright (C) 2015-2019  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 import os
 import logging
 
 from flask import request
 from functools import wraps
 
 from swh.core import config
 from swh.storage import get_storage as get_swhstorage
 from swh.core.api import (SWHServerAPIApp, decode_request,
                           error_handler,
                           encode_data_server as encode_data)
 from swh.core.statsd import statsd
 
 
 app = SWHServerAPIApp(__name__)
 storage = None
 
 
 OPERATIONS_METRIC = 'swh_storage_operations_total'
 OPERATIONS_UNIT_METRIC = "swh_storage_operations_{unit}_total"
 DURATION_METRIC = "swh_storage_request_duration_seconds"
 
 
 def timed(f):
     """Time that function!
 
     """
     @wraps(f)
     def d(*a, **kw):
         with statsd.timed(DURATION_METRIC, tags={'endpoint': f.__name__}):
             return f(*a, **kw)
 
     return d
 
 
 def encode(f):
     @wraps(f)
     def d(*a, **kw):
         r = f(*a, **kw)
         return encode_data(r)
 
     return d
 
 
 def send_metric(metric, count, method_name):
     """Send statsd metric with count for method `method_name`
 
     If count is 0, the metric is discarded.  If the metric is not
     parseable, the metric is discarded with a log message.
 
     Args:
         metric (str): Metric's name (e.g content:add, content:add:bytes)
         count (int): Associated value for the metric
         method_name (str): Method's name
 
     Returns:
         Bool to explicit if metric has been set or not
     """
     if count == 0:
         return False
 
     metric_type = metric.split(':')
     _length = len(metric_type)
     if _length == 2:
         object_type, operation = metric_type
         metric_name = OPERATIONS_METRIC
     elif _length == 3:
         object_type, operation, unit = metric_type
         metric_name = OPERATIONS_UNIT_METRIC.format(unit=unit)
     else:
         logging.warning('Skipping unknown metric {%s: %s}' % (
             metric, count))
         return False
 
     statsd.increment(
         metric_name, count, tags={
             'endpoint': method_name,
             'object_type': object_type,
             'operation': operation,
         })
     return True
 
 
 def process_metrics(f):
     """Increment object counters for the decorated function.
 
     """
     @wraps(f)
     def d(*a, **kw):
         r = f(*a, **kw)
         for metric, count in r.items():
             send_metric(metric=metric, count=count, method_name=f.__name__)
 
         return r
 
     return d
 
 
 @app.errorhandler(Exception)
 def my_error_handler(exception):
     return error_handler(exception, encode_data)
 
 
 def get_storage():
     global storage
     if not storage:
         storage = get_swhstorage(**app.config['storage'])
 
     return storage
 
 
 @app.route('/')
 @timed
 def index():
     return '''<html>
 <head><title>Software Heritage storage server</title></head>
 <body>
 <p>You have reached the
 <a href="https://www.softwareheritage.org/">Software Heritage</a>
 storage server.<br />
 See its
 <a href="https://docs.softwareheritage.org/devel/swh-storage/">documentation
 and API</a> for more information</p>
 </html>'''
 
 
 @app.route('/check_config', methods=['POST'])
 @timed
 def check_config():
     return encode_data(get_storage().check_config(**decode_request(request)))
 
 
 @app.route('/content/missing', methods=['POST'])
 @timed
 def content_missing():
     return encode_data(get_storage().content_missing(
         **decode_request(request)))
 
 
 @app.route('/content/missing/sha1', methods=['POST'])
 @timed
 def content_missing_per_sha1():
     return encode_data(get_storage().content_missing_per_sha1(
         **decode_request(request)))
 
 
 @app.route('/content/skipped/missing', methods=['POST'])
 @timed
 def skipped_content_missing():
     return encode_data(get_storage().skipped_content_missing(
         **decode_request(request)))
 
 
 @app.route('/content/present', methods=['POST'])
 @timed
 def content_find():
     return encode_data(get_storage().content_find(**decode_request(request)))
 
 
 @app.route('/content/add', methods=['POST'])
 @timed
 @encode
 @process_metrics
 def content_add():
     return get_storage().content_add(**decode_request(request))
 
 
 @app.route('/content/add_metadata', methods=['POST'])
 @timed
 @encode
 @process_metrics
 def content_add_metadata():
     return get_storage().content_add_metadata(**decode_request(request))
 
 
 @app.route('/content/update', methods=['POST'])
 @timed
 def content_update():
     return encode_data(get_storage().content_update(**decode_request(request)))
 
 
 @app.route('/content/data', methods=['POST'])
 @timed
 def content_get():
     return encode_data(get_storage().content_get(**decode_request(request)))
 
 
 @app.route('/content/metadata', methods=['POST'])
 @timed
 def content_get_metadata():
     return encode_data(get_storage().content_get_metadata(
         **decode_request(request)))
 
 
 @app.route('/content/range', methods=['POST'])
 @timed
 def content_get_range():
     return encode_data(get_storage().content_get_range(
         **decode_request(request)))
 
 
 @app.route('/directory/missing', methods=['POST'])
 @timed
 def directory_missing():
     return encode_data(get_storage().directory_missing(
         **decode_request(request)))
 
 
 @app.route('/directory/add', methods=['POST'])
 @timed
 @encode
 @process_metrics
 def directory_add():
     return get_storage().directory_add(**decode_request(request))
 
 
 @app.route('/directory/path', methods=['POST'])
 @timed
 def directory_entry_get_by_path():
     return encode_data(get_storage().directory_entry_get_by_path(
         **decode_request(request)))
 
 
 @app.route('/directory/ls', methods=['POST'])
 @timed
 def directory_ls():
     return encode_data(get_storage().directory_ls(
         **decode_request(request)))
 
 
 @app.route('/revision/add', methods=['POST'])
 @timed
 @encode
 @process_metrics
 def revision_add():
     return get_storage().revision_add(**decode_request(request))
 
 
 @app.route('/revision', methods=['POST'])
 @timed
 def revision_get():
     return encode_data(get_storage().revision_get(**decode_request(request)))
 
 
 @app.route('/revision/log', methods=['POST'])
 @timed
 def revision_log():
     return encode_data(get_storage().revision_log(**decode_request(request)))
 
 
 @app.route('/revision/shortlog', methods=['POST'])
 @timed
 def revision_shortlog():
     return encode_data(get_storage().revision_shortlog(
         **decode_request(request)))
 
 
 @app.route('/revision/missing', methods=['POST'])
 @timed
 def revision_missing():
     return encode_data(get_storage().revision_missing(
         **decode_request(request)))
 
 
 @app.route('/release/add', methods=['POST'])
 @timed
 @encode
 @process_metrics
 def release_add():
     return get_storage().release_add(**decode_request(request))
 
 
 @app.route('/release', methods=['POST'])
 @timed
 def release_get():
     return encode_data(get_storage().release_get(**decode_request(request)))
 
 
 @app.route('/release/missing', methods=['POST'])
 @timed
 def release_missing():
     return encode_data(get_storage().release_missing(
         **decode_request(request)))
 
 
 @app.route('/object/find_by_sha1_git', methods=['POST'])
 @timed
 def object_find_by_sha1_git():
     return encode_data(get_storage().object_find_by_sha1_git(
         **decode_request(request)))
 
 
 @app.route('/snapshot/add', methods=['POST'])
 @timed
 @encode
 @process_metrics
 def snapshot_add():
-    return get_storage().snapshot_add(**decode_request(request))
+    req_data = decode_request(request)
+    if 'snapshot' in req_data:
+        req_data['snapshots'] = req_data.pop('snapshot')
+    return get_storage().snapshot_add(**req_data)
 
 
 @app.route('/snapshot', methods=['POST'])
 @timed
 def snapshot_get():
     return encode_data(get_storage().snapshot_get(**decode_request(request)))
 
 
 @app.route('/snapshot/by_origin_visit', methods=['POST'])
 @timed
 def snapshot_get_by_origin_visit():
     return encode_data(get_storage().snapshot_get_by_origin_visit(
         **decode_request(request)))
 
 
 @app.route('/snapshot/latest', methods=['POST'])
 @timed
 def snapshot_get_latest():
     return encode_data(get_storage().snapshot_get_latest(
         **decode_request(request)))
 
 
 @app.route('/snapshot/count_branches', methods=['POST'])
 @timed
 def snapshot_count_branches():
     return encode_data(get_storage().snapshot_count_branches(
         **decode_request(request)))
 
 
 @app.route('/snapshot/get_branches', methods=['POST'])
 @timed
 def snapshot_get_branches():
     return encode_data(get_storage().snapshot_get_branches(
         **decode_request(request)))
 
 
 @app.route('/origin/get', methods=['POST'])
 @timed
 def origin_get():
     return encode_data(get_storage().origin_get(**decode_request(request)))
 
 
 @app.route('/origin/get_range', methods=['POST'])
 @timed
 def origin_get_range():
     return encode_data(get_storage().origin_get_range(
         **decode_request(request)))
 
 
 @app.route('/origin/search', methods=['POST'])
 @timed
 def origin_search():
     return encode_data(get_storage().origin_search(**decode_request(request)))
 
 
 @app.route('/origin/count', methods=['POST'])
 @timed
 def origin_count():
     return encode_data(get_storage().origin_count(**decode_request(request)))
 
 
 @app.route('/origin/add_multi', methods=['POST'])
 @timed
 @encode
 def origin_add():
     origins = get_storage().origin_add(**decode_request(request))
     send_metric('origin:add', count=len(origins), method_name='origin_add')
     return origins
 
 
 @app.route('/origin/add', methods=['POST'])
 @timed
 @encode
 def origin_add_one():
     origin = get_storage().origin_add_one(**decode_request(request))
     send_metric('origin:add', count=1, method_name='origin_add_one')
     return origin
 
 
 @app.route('/origin/visit/get', methods=['POST'])
 @timed
 def origin_visit_get():
     return encode_data(get_storage().origin_visit_get(
         **decode_request(request)))
 
 
 @app.route('/origin/visit/getby', methods=['POST'])
 @timed
 def origin_visit_get_by():
     return encode_data(
         get_storage().origin_visit_get_by(**decode_request(request)))
 
 
 @app.route('/origin/visit/add', methods=['POST'])
 @timed
 @encode
 def origin_visit_add():
     origin_visit = get_storage().origin_visit_add(
         **decode_request(request))
     send_metric('origin_visit:add', count=1, method_name='origin_visit')
     return origin_visit
 
 
 @app.route('/origin/visit/update', methods=['POST'])
 @timed
 def origin_visit_update():
     return encode_data(get_storage().origin_visit_update(
         **decode_request(request)))
 
 
 @app.route('/origin/visit/upsert', methods=['POST'])
 @timed
 def origin_visit_upsert():
     return encode_data(get_storage().origin_visit_upsert(
         **decode_request(request)))
 
 
 @app.route('/person', methods=['POST'])
 @timed
 def person_get():
     return encode_data(get_storage().person_get(**decode_request(request)))
 
 
 @app.route('/fetch_history', methods=['GET'])
 @timed
 def fetch_history_get():
     return encode_data(get_storage().fetch_history_get(request.args['id']))
 
 
 @app.route('/fetch_history/start', methods=['POST'])
 @timed
 def fetch_history_start():
     return encode_data(
         get_storage().fetch_history_start(**decode_request(request)))
 
 
 @app.route('/fetch_history/end', methods=['POST'])
 @timed
 def fetch_history_end():
     return encode_data(
         get_storage().fetch_history_end(**decode_request(request)))
 
 
 @app.route('/tool/data', methods=['POST'])
 @timed
 def tool_get():
     return encode_data(get_storage().tool_get(
         **decode_request(request)))
 
 
 @app.route('/tool/add', methods=['POST'])
 @timed
 @encode
 def tool_add():
     tools = get_storage().tool_add(**decode_request(request))
     send_metric('tool:add', count=len(tools), method_name='tool_add')
     return tools
 
 
 @app.route('/origin/metadata/add', methods=['POST'])
 @timed
 @encode
 def origin_metadata_add():
     origin_metadata = get_storage().origin_metadata_add(
         **decode_request(request))
     send_metric(
         'origin_metadata:add', count=1, method_name='origin_metadata_add')
     return origin_metadata
 
 
 @app.route('/origin/metadata/get', methods=['POST'])
 @timed
 def origin_metadata_get_by():
     return encode_data(get_storage().origin_metadata_get_by(**decode_request(
                                                        request)))
 
 
 @app.route('/provider/add', methods=['POST'])
 @timed
 @encode
 def metadata_provider_add():
     metadata_provider = get_storage().metadata_provider_add(**decode_request(
         request))
     send_metric(
         'metadata_provider:add', count=1, method_name='metadata_provider')
     return metadata_provider
 
 
 @app.route('/provider/get', methods=['POST'])
 @timed
 def metadata_provider_get():
     return encode_data(get_storage().metadata_provider_get(**decode_request(
                                                        request)))
 
 
 @app.route('/provider/getby', methods=['POST'])
 @timed
 def metadata_provider_get_by():
     return encode_data(get_storage().metadata_provider_get_by(**decode_request(
                                                        request)))
 
 
 @app.route('/stat/counters', methods=['GET'])
 @timed
 def stat_counters():
     return encode_data(get_storage().stat_counters())
 
 
 @app.route('/algos/diff_directories', methods=['POST'])
 @timed
 def diff_directories():
     return encode_data(get_storage().diff_directories(
         **decode_request(request)))
 
 
 @app.route('/algos/diff_revisions', methods=['POST'])
 @timed
 def diff_revisions():
     return encode_data(get_storage().diff_revisions(**decode_request(request)))
 
 
 @app.route('/algos/diff_revision', methods=['POST'])
 @timed
 def diff_revision():
     return encode_data(get_storage().diff_revision(**decode_request(request)))
 
 
 api_cfg = None
 
 
 def load_and_check_config(config_file, type='local'):
     """Check the minimal configuration is set to run the api or raise an
        error explanation.
 
     Args:
         config_file (str): Path to the configuration file to load
         type (str): configuration type. For 'local' type, more
                     checks are done.
 
     Raises:
         Error if the setup is not as expected
 
     Returns:
         configuration as a dict
 
     """
     if not config_file:
         raise EnvironmentError('Configuration file must be defined')
 
     if not os.path.exists(config_file):
         raise FileNotFoundError('Configuration file %s does not exist' % (
             config_file, ))
 
     cfg = config.read(config_file)
     if 'storage' not in cfg:
         raise KeyError("Missing '%storage' configuration")
 
     if type == 'local':
         vcfg = cfg['storage']
         cls = vcfg.get('cls')
         if cls != 'local':
             raise ValueError(
                 "The storage backend can only be started with a 'local' "
                 "configuration")
 
         args = vcfg['args']
         for key in ('db', 'objstorage'):
             if not args.get(key):
                 raise ValueError(
                     "Invalid configuration; missing '%s' config entry" % key)
 
     return cfg
 
 
 def make_app_from_configfile():
     """Run the WSGI app from the webserver, loading the configuration from
        a configuration file.
 
        SWH_CONFIG_FILENAME environment variable defines the
        configuration path to load.
 
     """
     global api_cfg
     if not api_cfg:
         config_file = os.environ.get('SWH_CONFIG_FILENAME')
         api_cfg = load_and_check_config(config_file)
         app.config.update(api_cfg)
     handler = logging.StreamHandler()
     app.logger.addHandler(handler)
     return app
 
 
 if __name__ == '__main__':
     print('Deprecated. Use swh-storage')
diff --git a/swh/storage/in_memory.py b/swh/storage/in_memory.py
index 115f273b..c1857321 100644
--- a/swh/storage/in_memory.py
+++ b/swh/storage/in_memory.py
@@ -1,1537 +1,1537 @@
 # Copyright (C) 2015-2019  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 import re
 import bisect
 import dateutil
 import collections
 from collections import defaultdict
 import copy
 import datetime
 import itertools
 import random
 import warnings
 
 from swh.model.hashutil import DEFAULT_ALGORITHMS
 from swh.model.identifiers import normalize_timestamp
 from swh.objstorage import get_objstorage
 from swh.objstorage.exc import ObjNotFoundError
 
 from .journal_writer import get_journal_writer
 
 # Max block size of contents to return
 BULK_BLOCK_CONTENT_LEN_MAX = 10000
 
 
 def now():
     return datetime.datetime.now(tz=datetime.timezone.utc)
 
 
 class Storage:
     def __init__(self, journal_writer=None):
         self._contents = {}
         self._content_indexes = defaultdict(lambda: defaultdict(set))
 
         self._directories = {}
         self._revisions = {}
         self._releases = {}
         self._snapshots = {}
         self._origins = []
         self._origin_visits = []
         self._persons = []
         self._origin_metadata = defaultdict(list)
         self._tools = {}
         self._metadata_providers = {}
         self._objects = defaultdict(list)
 
         # ideally we would want a skip list for both fast inserts and searches
         self._sorted_sha1s = []
 
         self.objstorage = get_objstorage('memory', {})
         if journal_writer:
             self.journal_writer = get_journal_writer(**journal_writer)
         else:
             self.journal_writer = None
 
     def check_config(self, *, check_write):
         """Check that the storage is configured and ready to go."""
         return True
 
     def _content_add(self, contents, with_data):
         if self.journal_writer:
             for content in contents:
                 if 'data' in content:
                     content = content.copy()
                     del content['data']
                 self.journal_writer.write_addition('content', content)
 
         count_contents = 0
         count_content_added = 0
         count_content_bytes_added = 0
 
         for content in contents:
             key = self._content_key(content)
             if key in self._contents:
                 continue
             for algorithm in DEFAULT_ALGORITHMS:
                 if content[algorithm] in self._content_indexes[algorithm]:
                     from . import HashCollision
                     raise HashCollision(algorithm, content[algorithm], key)
             for algorithm in DEFAULT_ALGORITHMS:
                 self._content_indexes[algorithm][content[algorithm]].add(key)
             self._objects[content['sha1_git']].append(
                 ('content', content['sha1']))
             self._contents[key] = copy.deepcopy(content)
             bisect.insort(self._sorted_sha1s, content['sha1'])
             count_contents += 1
             if self._contents[key]['status'] == 'visible':
                 count_content_added += 1
                 if with_data:
                     content_data = self._contents[key].pop('data')
                     count_content_bytes_added += len(content_data)
                     self.objstorage.add(content_data, content['sha1'])
 
         summary = {
             'content:add': count_content_added,
             'skipped_content:add': count_contents - count_content_added,
         }
 
         if with_data:
-            summary['content:bytes:add'] = count_content_bytes_added
+            summary['content:add:bytes'] = count_content_bytes_added
 
         return summary
 
     def content_add(self, contents):
         """Add content blobs to the storage
 
         Args:
             content (iterable): iterable of dictionaries representing
                 individual pieces of content to add. Each dictionary has the
                 following keys:
 
                 - data (bytes): the actual content
                 - length (int): content length (default: -1)
                 - one key for each checksum algorithm in
                   :data:`swh.model.hashutil.DEFAULT_ALGORITHMS`, mapped to the
                   corresponding checksum
                 - status (str): one of visible, hidden, absent
                 - reason (str): if status = absent, the reason why
                 - origin (int): if status = absent, the origin we saw the
                   content in
 
         Raises:
             HashCollision in case of collision
 
         Returns:
             Summary dict with the following key and associated values:
 
                 content:add: New contents added
                 content_bytes:add: Sum of the contents' length data
                 skipped_content:add: New skipped contents (no data) added
 
         """
         contents = [dict(c.items()) for c in contents]  # semi-shallow copy
         now = datetime.datetime.now(tz=datetime.timezone.utc)
         for item in contents:
             item['ctime'] = now
         return self._content_add(contents, with_data=True)
 
     def content_add_metadata(self, contents):
         """Add content metadata to the storage (like `content_add`, but
         without inserting to the objstorage).
 
         Args:
             content (iterable): iterable of dictionaries representing
                 individual pieces of content to add. Each dictionary has the
                 following keys:
 
                 - length (int): content length (default: -1)
                 - one key for each checksum algorithm in
                   :data:`swh.model.hashutil.DEFAULT_ALGORITHMS`, mapped to the
                   corresponding checksum
                 - status (str): one of visible, hidden, absent
                 - reason (str): if status = absent, the reason why
                 - origin (int): if status = absent, the origin we saw the
                   content in
                 - ctime (datetime): time of insertion in the archive
 
         Raises:
             HashCollision in case of collision
 
         Returns:
             Summary dict with the following key and associated values:
 
                 content:add: New contents added
                 skipped_content:add: New skipped contents (no data) added
 
         """
         return self._content_add(contents, with_data=False)
 
     def content_get(self, ids):
         """Retrieve in bulk contents and their data.
 
         This function may yield more blobs than provided sha1 identifiers,
         in case they collide.
 
         Args:
             content: iterables of sha1
 
         Yields:
             Dict[str, bytes]: Generates streams of contents as dict with their
                 raw data:
 
                 - sha1 (bytes): content id
                 - data (bytes): content's raw data
 
         Raises:
             ValueError in case of too much contents are required.
             cf. BULK_BLOCK_CONTENT_LEN_MAX
 
         """
         # FIXME: Make this method support slicing the `data`.
         if len(ids) > BULK_BLOCK_CONTENT_LEN_MAX:
             raise ValueError(
                 "Sending at most %s contents." % BULK_BLOCK_CONTENT_LEN_MAX)
         for obj_id in ids:
             try:
                 data = self.objstorage.get(obj_id)
             except ObjNotFoundError:
                 yield None
                 continue
 
             yield {'sha1': obj_id, 'data': data}
 
     def content_get_range(self, start, end, limit=1000, db=None, cur=None):
         """Retrieve contents within range [start, end] bound by limit.
 
         Note that this function may return more than one blob per hash. The
         limit is enforced with multiplicity (ie. two blobs with the same hash
         will count twice toward the limit).
 
         Args:
             **start** (bytes): Starting identifier range (expected smaller
                            than end)
             **end** (bytes): Ending identifier range (expected larger
                              than start)
             **limit** (int): Limit result (default to 1000)
 
         Returns:
             a dict with keys:
             - contents [dict]: iterable of contents in between the range.
             - next (bytes): There remains content in the range
               starting from this next sha1
 
         """
         if limit is None:
             raise ValueError('Development error: limit should not be None')
         from_index = bisect.bisect_left(self._sorted_sha1s, start)
         sha1s = itertools.islice(self._sorted_sha1s, from_index, None)
         sha1s = ((sha1, content_key)
                  for sha1 in sha1s
                  for content_key in self._content_indexes['sha1'][sha1])
         matched = []
         next_content = None
         for sha1, key in sha1s:
             if sha1 > end:
                 break
             if len(matched) >= limit:
                 next_content = sha1
                 break
             matched.append({
                 **self._contents[key],
             })
         return {
             'contents': matched,
             'next': next_content,
         }
 
     def content_get_metadata(self, sha1s):
         """Retrieve content metadata in bulk
 
         Args:
             content: iterable of content identifiers (sha1)
 
         Returns:
             an iterable with content metadata corresponding to the given ids
         """
         # FIXME: the return value should be a mapping from search key to found
         # content*s*
         for sha1 in sha1s:
             if sha1 in self._content_indexes['sha1']:
                 objs = self._content_indexes['sha1'][sha1]
                 # FIXME: rather than selecting one of the objects with that
                 # hash, we should return all of them. See:
                 # https://forge.softwareheritage.org/D645?id=1994#inline-3389
                 key = random.sample(objs, 1)[0]
                 data = copy.deepcopy(self._contents[key])
                 data.pop('ctime')
                 yield data
             else:
                 # FIXME: should really be None
                 yield {
                     'sha1': sha1,
                     'sha1_git': None,
                     'sha256': None,
                     'blake2s256': None,
                     'length': None,
                     'status': None,
                 }
 
     def content_find(self, content):
         if not set(content).intersection(DEFAULT_ALGORITHMS):
             raise ValueError('content keys must contain at least one of: '
                              '%s' % ', '.join(sorted(DEFAULT_ALGORITHMS)))
         found = []
         for algo in DEFAULT_ALGORITHMS:
             hash = content.get(algo)
             if hash and hash in self._content_indexes[algo]:
                 found.append(self._content_indexes[algo][hash])
         if not found:
             return
         keys = list(set.intersection(*found))
 
         # FIXME: should really be a list of all the objects found
         return copy.deepcopy(self._contents[keys[0]])
 
     def content_missing(self, contents, key_hash='sha1'):
         """List content missing from storage
 
         Args:
             contents ([dict]): iterable of dictionaries whose keys are
                                either 'length' or an item of
                                :data:`swh.model.hashutil.ALGORITHMS`;
                                mapped to the corresponding checksum
                                (or length).
 
             key_hash (str): name of the column to use as hash id
                             result (default: 'sha1')
 
         Returns:
             iterable ([bytes]): missing content ids (as per the
             key_hash column)
         """
         for content in contents:
             for (algo, hash_) in content.items():
                 if algo not in DEFAULT_ALGORITHMS:
                     continue
                 if hash_ not in self._content_indexes.get(algo, []):
                     yield content[key_hash]
                     break
             else:
                 # content_find cannot return None here, because we checked
                 # above that there is a content with matching hashes.
                 if self.content_find(content)['status'] == 'missing':
                     yield content[key_hash]
 
     def content_missing_per_sha1(self, contents):
         """List content missing from storage based only on sha1.
 
         Args:
             contents: Iterable of sha1 to check for absence.
 
         Returns:
             iterable: missing ids
 
         Raises:
             TODO: an exception when we get a hash collision.
 
         """
         for content in contents:
             if content not in self._content_indexes['sha1']:
                 yield content
 
     def directory_add(self, directories):
         """Add directories to the storage
 
         Args:
             directories (iterable): iterable of dictionaries representing the
                 individual directories to add. Each dict has the following
                 keys:
 
                 - id (sha1_git): the id of the directory to add
                 - entries (list): list of dicts for each entry in the
                       directory.  Each dict has the following keys:
 
                       - name (bytes)
                       - type (one of 'file', 'dir', 'rev'): type of the
                         directory entry (file, directory, revision)
                       - target (sha1_git): id of the object pointed at by the
                         directory entry
                       - perms (int): entry permissions
         Returns:
             Summary dict of keys with associated count as values:
 
                 directory:add: Number of directories actually added
 
         """
         if self.journal_writer:
             self.journal_writer.write_additions('directory', directories)
 
         count = 0
         for directory in directories:
             if directory['id'] not in self._directories:
                 count += 1
                 self._directories[directory['id']] = copy.deepcopy(directory)
                 self._objects[directory['id']].append(
                     ('directory', directory['id']))
 
         return {'directory:add': count}
 
     def directory_missing(self, directory_ids):
         """List directories missing from storage
 
         Args:
             directories (iterable): an iterable of directory ids
 
         Yields:
             missing directory ids
 
         """
         for id in directory_ids:
             if id not in self._directories:
                 yield id
 
     def _join_dentry_to_content(self, dentry):
         keys = (
             'status',
             'sha1',
             'sha1_git',
             'sha256',
             'length',
         )
         ret = dict.fromkeys(keys)
         ret.update(dentry)
         if ret['type'] == 'file':
             content = self.content_find({'sha1_git': ret['target']})
             if content:
                 for key in keys:
                     ret[key] = content[key]
         return ret
 
     def _directory_ls(self, directory_id, recursive, prefix=b''):
         if directory_id in self._directories:
             for entry in self._directories[directory_id]['entries']:
                 ret = self._join_dentry_to_content(entry)
                 ret['name'] = prefix + ret['name']
                 ret['dir_id'] = directory_id
                 yield ret
                 if recursive and ret['type'] == 'dir':
                     yield from self._directory_ls(
                         ret['target'], True, prefix + ret['name'] + b'/')
 
     def directory_ls(self, directory_id, recursive=False):
         """Get entries for one directory.
 
         Args:
             - directory: the directory to list entries from.
             - recursive: if flag on, this list recursively from this directory.
 
         Returns:
             List of entries for such directory.
 
         If `recursive=True`, names in the path of a dir/file not at the
         root are concatenated with a slash (`/`).
         """
         yield from self._directory_ls(directory_id, recursive)
 
     def directory_entry_get_by_path(self, directory, paths):
         """Get the directory entry (either file or dir) from directory with path.
 
         Args:
             - directory: sha1 of the top level directory
             - paths: path to lookup from the top level directory. From left
               (top) to right (bottom).
 
         Returns:
             The corresponding directory entry if found, None otherwise.
 
         """
         if not paths:
             return
 
         contents = list(self.directory_ls(directory))
 
         if not contents:
             return
 
         def _get_entry(entries, name):
             for entry in entries:
                 if entry['name'] == name:
                     return entry
 
         first_item = _get_entry(contents, paths[0])
 
         if len(paths) == 1:
             return first_item
 
         if not first_item or first_item['type'] != 'dir':
             return
 
         return self.directory_entry_get_by_path(
                 first_item['target'], paths[1:])
 
     def revision_add(self, revisions):
         """Add revisions to the storage
 
         Args:
             revisions (Iterable[dict]): iterable of dictionaries representing
                 the individual revisions to add. Each dict has the following
                 keys:
 
                 - **id** (:class:`sha1_git`): id of the revision to add
                 - **date** (:class:`dict`): date the revision was written
                 - **committer_date** (:class:`dict`): date the revision got
                   added to the origin
                 - **type** (one of 'git', 'tar'): type of the
                   revision added
                 - **directory** (:class:`sha1_git`): the directory the
                   revision points at
                 - **message** (:class:`bytes`): the message associated with
                   the revision
                 - **author** (:class:`Dict[str, bytes]`): dictionary with
                   keys: name, fullname, email
                 - **committer** (:class:`Dict[str, bytes]`): dictionary with
                   keys: name, fullname, email
                 - **metadata** (:class:`jsonb`): extra information as
                   dictionary
                 - **synthetic** (:class:`bool`): revision's nature (tarball,
                   directory creates synthetic revision`)
                 - **parents** (:class:`list[sha1_git]`): the parents of
                   this revision
 
         date dictionaries have the form defined in :mod:`swh.model`.
 
         Returns:
             Summary dict of keys with associated count as values
 
                 revision_added: New objects actually stored in db
 
         """
         if self.journal_writer:
             self.journal_writer.write_additions('revision', revisions)
 
         count = 0
         for revision in revisions:
             if revision['id'] not in self._revisions:
                 self._revisions[revision['id']] = rev = copy.deepcopy(revision)
                 self._person_add(rev['committer'])
                 self._person_add(rev['author'])
                 rev['date'] = normalize_timestamp(rev.get('date'))
                 rev['committer_date'] = normalize_timestamp(
                         rev.get('committer_date'))
                 self._objects[revision['id']].append(
                     ('revision', revision['id']))
                 count += 1
 
         return {'revision:add': count}
 
     def revision_missing(self, revision_ids):
         """List revisions missing from storage
 
         Args:
             revisions (iterable): revision ids
 
         Yields:
             missing revision ids
 
         """
         for id in revision_ids:
             if id not in self._revisions:
                 yield id
 
     def revision_get(self, revision_ids):
         for id in revision_ids:
             yield copy.deepcopy(self._revisions.get(id))
 
     def _get_parent_revs(self, rev_id, seen, limit):
         if limit and len(seen) >= limit:
             return
         if rev_id in seen or rev_id not in self._revisions:
             return
         seen.add(rev_id)
         yield self._revisions[rev_id]
         for parent in self._revisions[rev_id]['parents']:
             yield from self._get_parent_revs(parent, seen, limit)
 
     def revision_log(self, revision_ids, limit=None):
         """Fetch revision entry from the given root revisions.
 
         Args:
             revisions: array of root revision to lookup
             limit: limitation on the output result. Default to None.
 
         Yields:
             List of revision log from such revisions root.
 
         """
         seen = set()
         for rev_id in revision_ids:
             yield from self._get_parent_revs(rev_id, seen, limit)
 
     def revision_shortlog(self, revisions, limit=None):
         """Fetch the shortlog for the given revisions
 
         Args:
             revisions: list of root revisions to lookup
             limit: depth limitation for the output
 
         Yields:
             a list of (id, parents) tuples.
 
         """
         yield from ((rev['id'], rev['parents'])
                     for rev in self.revision_log(revisions, limit))
 
     def release_add(self, releases):
         """Add releases to the storage
 
         Args:
             releases (Iterable[dict]): iterable of dictionaries representing
                 the individual releases to add. Each dict has the following
                 keys:
 
                 - **id** (:class:`sha1_git`): id of the release to add
                 - **revision** (:class:`sha1_git`): id of the revision the
                   release points to
                 - **date** (:class:`dict`): the date the release was made
                 - **name** (:class:`bytes`): the name of the release
                 - **comment** (:class:`bytes`): the comment associated with
                   the release
                 - **author** (:class:`Dict[str, bytes]`): dictionary with
                   keys: name, fullname, email
 
         the date dictionary has the form defined in :mod:`swh.model`.
 
         Returns:
             Summary dict of keys with associated count as values
 
                 release:add: New objects contents actually stored in db
 
         """
         if self.journal_writer:
             self.journal_writer.write_additions('release', releases)
 
         count = 0
         for rel in releases:
             if rel['id'] not in self._releases:
                 rel = copy.deepcopy(rel)
                 rel['date'] = normalize_timestamp(rel['date'])
                 if rel['author']:
                     self._person_add(rel['author'])
                 self._objects[rel['id']].append(
                     ('release', rel['id']))
                 self._releases[rel['id']] = rel
                 count += 1
 
         return {'release:add': count}
 
     def release_missing(self, releases):
         """List releases missing from storage
 
         Args:
             releases: an iterable of release ids
 
         Returns:
             a list of missing release ids
 
         """
         yield from (rel for rel in releases if rel not in self._releases)
 
     def release_get(self, releases):
         """Given a list of sha1, return the releases's information
 
         Args:
             releases: list of sha1s
 
         Yields:
             dicts with the same keys as those given to `release_add`
             (or ``None`` if a release does not exist)
 
         """
         for rel_id in releases:
             yield copy.deepcopy(self._releases.get(rel_id))
 
     def snapshot_add(self, snapshots, legacy_arg1=None, legacy_arg2=None):
         """Add a snapshot to the storage
 
         Args:
             snapshot ([dict]): the snapshots to add, containing the
               following keys:
 
               - **id** (:class:`bytes`): id of the snapshot
               - **branches** (:class:`dict`): branches the snapshot contains,
                 mapping the branch name (:class:`bytes`) to the branch target,
                 itself a :class:`dict` (or ``None`` if the branch points to an
                 unknown object)
 
                 - **target_type** (:class:`str`): one of ``content``,
                   ``directory``, ``revision``, ``release``,
                   ``snapshot``, ``alias``
                 - **target** (:class:`bytes`): identifier of the target
                   (currently a ``sha1_git`` for all object kinds, or the name
                   of the target branch for aliases)
 
         Raises:
             ValueError: if the origin's or visit's identifier does not exist.
 
         Returns:
             Summary dict of keys with associated count as values
 
                 snapshot_added: Count of object actually stored in db
 
         """
         if legacy_arg1:
             assert legacy_arg2
             (origin, visit, snapshots) = \
                 (snapshots, legacy_arg1, [legacy_arg2])
         else:
             origin = visit = None
 
         count = 0
         for snapshot in snapshots:
             snapshot_id = snapshot['id']
             if snapshot_id not in self._snapshots:
                 if self.journal_writer:
                     self.journal_writer.write_addition('snapshot', snapshot)
 
                 self._snapshots[snapshot_id] = {
                     'id': snapshot_id,
                     'branches': copy.deepcopy(snapshot['branches']),
                     '_sorted_branch_names': sorted(snapshot['branches'])
                     }
                 self._objects[snapshot_id].append(('snapshot', snapshot_id))
                 count += 1
 
         if origin:
             # Legacy API, there can be only one snapshot
             self.origin_visit_update(
                 origin, visit, snapshot=snapshots[0]['id'])
 
         return {'snapshot:add': count}
 
     def snapshot_get(self, snapshot_id):
         """Get the content, possibly partial, of a snapshot with the given id
 
         The branches of the snapshot are iterated in the lexicographical
         order of their names.
 
         .. warning:: At most 1000 branches contained in the snapshot will be
             returned for performance reasons. In order to browse the whole
             set of branches, the method :meth:`snapshot_get_branches`
             should be used instead.
 
         Args:
             snapshot_id (bytes): identifier of the snapshot
         Returns:
             dict: a dict with three keys:
                 * **id**: identifier of the snapshot
                 * **branches**: a dict of branches contained in the snapshot
                   whose keys are the branches' names.
                 * **next_branch**: the name of the first branch not returned
                   or :const:`None` if the snapshot has less than 1000
                   branches.
         """
         return self.snapshot_get_branches(snapshot_id)
 
     def snapshot_get_by_origin_visit(self, origin, visit):
         """Get the content, possibly partial, of a snapshot for the given origin visit
 
         The branches of the snapshot are iterated in the lexicographical
         order of their names.
 
         .. warning:: At most 1000 branches contained in the snapshot will be
             returned for performance reasons. In order to browse the whole
             set of branches, the method :meth:`snapshot_get_branches`
             should be used instead.
 
         Args:
             origin (int): the origin's identifier
             visit (int): the visit's identifier
         Returns:
             dict: None if the snapshot does not exist;
               a dict with three keys otherwise:
                 * **id**: identifier of the snapshot
                 * **branches**: a dict of branches contained in the snapshot
                   whose keys are the branches' names.
                 * **next_branch**: the name of the first branch not returned
                   or :const:`None` if the snapshot has less than 1000
                   branches.
 
         """
         if origin > len(self._origins) or \
            visit > len(self._origin_visits[origin-1]):
             return None
         snapshot_id = self._origin_visits[origin-1][visit-1]['snapshot']
         if snapshot_id:
             return self.snapshot_get(snapshot_id)
         else:
             return None
 
     def snapshot_get_latest(self, origin, allowed_statuses=None):
         """Get the content, possibly partial, of the latest snapshot for the
         given origin, optionally only from visits that have one of the given
         allowed_statuses
 
         The branches of the snapshot are iterated in the lexicographical
         order of their names.
 
         .. warning:: At most 1000 branches contained in the snapshot will be
             returned for performance reasons. In order to browse the whole
             set of branches, the method :meth:`snapshot_get_branches`
             should be used instead.
 
         Args:
             origin (int): the origin's identifier
             allowed_statuses (list of str): list of visit statuses considered
                 to find the latest snapshot for the visit. For instance,
                 ``allowed_statuses=['full']`` will only consider visits that
                 have successfully run to completion.
         Returns:
             dict: a dict with three keys:
                 * **id**: identifier of the snapshot
                 * **branches**: a dict of branches contained in the snapshot
                   whose keys are the branches' names.
                 * **next_branch**: the name of the first branch not returned
                   or :const:`None` if the snapshot has less than 1000
                   branches.
         """
         visits = self._origin_visits[origin-1]
         if allowed_statuses is not None:
             visits = [visit for visit in visits
                       if visit['status'] in allowed_statuses]
         snapshot = None
         for visit in sorted(visits, key=lambda v: (v['date'], v['visit']),
                             reverse=True):
             snapshot_id = visit['snapshot']
             snapshot = self.snapshot_get(snapshot_id)
             if snapshot:
                 break
 
         return snapshot
 
     def snapshot_count_branches(self, snapshot_id, db=None, cur=None):
         """Count the number of branches in the snapshot with the given id
 
         Args:
             snapshot_id (bytes): identifier of the snapshot
 
         Returns:
             dict: A dict whose keys are the target types of branches and
             values their corresponding amount
         """
         branches = list(self._snapshots[snapshot_id]['branches'].values())
         return collections.Counter(branch['target_type'] if branch else None
                                    for branch in branches)
 
     def snapshot_get_branches(self, snapshot_id, branches_from=b'',
                               branches_count=1000, target_types=None):
         """Get the content, possibly partial, of a snapshot with the given id
 
         The branches of the snapshot are iterated in the lexicographical
         order of their names.
 
         Args:
             snapshot_id (bytes): identifier of the snapshot
             branches_from (bytes): optional parameter used to skip branches
                 whose name is lesser than it before returning them
             branches_count (int): optional parameter used to restrain
                 the amount of returned branches
             target_types (list): optional parameter used to filter the
                 target types of branch to return (possible values that can be
                 contained in that list are `'content', 'directory',
                 'revision', 'release', 'snapshot', 'alias'`)
         Returns:
             dict: None if the snapshot does not exist;
               a dict with three keys otherwise:
                 * **id**: identifier of the snapshot
                 * **branches**: a dict of branches contained in the snapshot
                   whose keys are the branches' names.
                 * **next_branch**: the name of the first branch not returned
                   or :const:`None` if the snapshot has less than
                   `branches_count` branches after `branches_from` included.
         """
         snapshot = self._snapshots.get(snapshot_id)
         if snapshot is None:
             return None
         sorted_branch_names = snapshot['_sorted_branch_names']
         from_index = bisect.bisect_left(
                 sorted_branch_names, branches_from)
         if target_types:
             next_branch = None
             branches = {}
             for branch_name in sorted_branch_names[from_index:]:
                 branch = snapshot['branches'][branch_name]
                 if branch and branch['target_type'] in target_types:
                     if len(branches) < branches_count:
                         branches[branch_name] = branch
                     else:
                         next_branch = branch_name
                         break
         else:
             # As there is no 'target_types', we can do that much faster
             to_index = from_index + branches_count
             returned_branch_names = sorted_branch_names[from_index:to_index]
             branches = {branch_name: snapshot['branches'][branch_name]
                         for branch_name in returned_branch_names}
             if to_index >= len(sorted_branch_names):
                 next_branch = None
             else:
                 next_branch = sorted_branch_names[to_index]
         return {
                 'id': snapshot_id,
                 'branches': branches,
                 'next_branch': next_branch,
                 }
 
     def object_find_by_sha1_git(self, ids, db=None, cur=None):
         """Return the objects found with the given ids.
 
         Args:
             ids: a generator of sha1_gits
 
         Returns:
             dict: a mapping from id to the list of objects found. Each object
             found is itself a dict with keys:
 
             - sha1_git: the input id
             - type: the type of object found
             - id: the id of the object found
             - object_id: the numeric id of the object found.
 
         """
         ret = {}
         for id_ in ids:
             objs = self._objects.get(id_, [])
             ret[id_] = [{
                     'sha1_git': id_,
                     'type': obj[0],
                     'id': obj[1],
                     'object_id': id_,
                     } for obj in objs]
         return ret
 
     def origin_get(self, origins):
         """Return origins, either all identified by their ids or all
         identified by tuples (type, url).
 
         Args:
             origin: a list of dictionaries representing the individual
                 origins to find.
                 These dicts have either the keys type and url:
 
                 - type (FIXME: enum TBD): the origin type ('git', 'wget', ...)
                 - url (bytes): the url the origin points to
 
                 or the id:
 
                 - id (int): the origin's identifier
 
         Returns:
             dict: the origin dictionary with the keys:
 
             - id: origin's id
             - type: origin's type
             - url: origin's url
 
         Raises:
             ValueError: if the keys does not match (url and type) nor id.
 
         """
         if isinstance(origins, dict):
             # Old API
             return_single = True
             origins = [origins]
         else:
             return_single = False
 
         # Sanity check to be error-compatible with the pgsql backend
         if any('id' in origin for origin in origins) \
                 and not all('id' in origin for origin in origins):
             raise ValueError(
                 'Either all origins or none at all should have an "id".')
         if any('type' in origin and 'url' in origin for origin in origins) \
                 and not all('type' in origin and 'url' in origin
                             for origin in origins):
             raise ValueError(
                 'Either all origins or none at all should have a '
                 '"type" and an "url".')
 
         results = []
         for origin in origins:
             if 'id' in origin:
                 origin_id = origin['id']
             elif 'type' in origin and 'url' in origin:
                 origin_id = self._origin_id(origin)
             else:
                 raise ValueError(
                     'Origin must have either id or (type and url).')
             origin = None
             # self._origin_id can return None
             if origin_id is not None and origin_id <= len(self._origins):
                 origin = copy.deepcopy(self._origins[origin_id-1])
                 origin['id'] = origin_id
             results.append(origin)
 
         if return_single:
             assert len(results) == 1
             return results[0]
         else:
             return results
 
     def origin_get_range(self, origin_from=1, origin_count=100):
         """Retrieve ``origin_count`` origins whose ids are greater
         or equal than ``origin_from``.
 
         Origins are sorted by id before retrieving them.
 
         Args:
             origin_from (int): the minimum id of origins to retrieve
             origin_count (int): the maximum number of origins to retrieve
 
         Yields:
             dicts containing origin information as returned
             by :meth:`swh.storage.in_memory.Storage.origin_get`.
         """
         origin_from = max(origin_from, 1)
         if origin_from <= len(self._origins):
             max_idx = origin_from + origin_count - 1
             if max_idx > len(self._origins):
                 max_idx = len(self._origins)
             for idx in range(origin_from-1, max_idx):
                 yield copy.deepcopy(self._origins[idx])
 
     def origin_search(self, url_pattern, offset=0, limit=50,
                       regexp=False, with_visit=False, db=None, cur=None):
         """Search for origins whose urls contain a provided string pattern
         or match a provided regular expression.
         The search is performed in a case insensitive way.
 
         Args:
             url_pattern (str): the string pattern to search for in origin urls
             offset (int): number of found origins to skip before returning
                 results
             limit (int): the maximum number of found origins to return
             regexp (bool): if True, consider the provided pattern as a regular
                 expression and return origins whose urls match it
             with_visit (bool): if True, filter out origins with no visit
 
         Returns:
             An iterable of dict containing origin information as returned
             by :meth:`swh.storage.storage.Storage.origin_get`.
         """
         origins = self._origins
         if regexp:
             pat = re.compile(url_pattern)
             origins = [orig for orig in origins if pat.match(orig['url'])]
         else:
             origins = [orig for orig in origins if url_pattern in orig['url']]
         if with_visit:
             origins = [orig for orig in origins
                        if len(self._origin_visits[orig['id']-1]) > 0]
 
         origins = copy.deepcopy(origins[offset:offset+limit])
         return origins
 
     def origin_count(self, url_pattern, regexp=False, with_visit=False,
                      db=None, cur=None):
         """Count origins whose urls contain a provided string pattern
         or match a provided regular expression.
         The pattern search in origin urls is performed in a case insensitive
         way.
 
         Args:
             url_pattern (str): the string pattern to search for in origin urls
             regexp (bool): if True, consider the provided pattern as a regular
                 expression and return origins whose urls match it
             with_visit (bool): if True, filter out origins with no visit
 
         Returns:
             int: The number of origins matching the search criterion.
         """
         return len(self.origin_search(url_pattern, regexp=regexp,
                                       with_visit=with_visit,
                                       limit=len(self._origins)))
 
     def origin_add(self, origins):
         """Add origins to the storage
 
         Args:
             origins: list of dictionaries representing the individual origins,
                 with the following keys:
 
                 - type: the origin type ('git', 'svn', 'deb', ...)
                 - url (bytes): the url the origin points to
 
         Returns:
             list: given origins as dict updated with their id
 
         """
         origins = copy.deepcopy(origins)
         for origin in origins:
             origin['id'] = self.origin_add_one(origin)
         return origins
 
     def origin_add_one(self, origin):
         """Add origin to the storage
 
         Args:
             origin: dictionary representing the individual origin to add. This
                 dict has the following keys:
 
                 - type (FIXME: enum TBD): the origin type ('git', 'wget', ...)
                 - url (bytes): the url the origin points to
 
         Returns:
             the id of the added origin, or of the identical one that already
             exists.
 
         """
         origin = copy.deepcopy(origin)
         assert 'id' not in origin
         origin_id = self._origin_id(origin)
         if origin_id is None:
             if self.journal_writer:
                 self.journal_writer.write_addition('origin', origin)
             # origin ids are in the range [1, +inf[
             origin_id = len(self._origins) + 1
             origin['id'] = origin_id
             self._origins.append(origin)
             self._origin_visits.append([])
             key = (origin['type'], origin['url'])
             self._objects[key].append(('origin', origin_id))
         else:
             origin['id'] = origin_id
 
         return origin_id
 
     def fetch_history_start(self, origin_id):
         """Add an entry for origin origin_id in fetch_history. Returns the id
         of the added fetch_history entry
         """
         pass
 
     def fetch_history_end(self, fetch_history_id, data):
         """Close the fetch_history entry with id `fetch_history_id`, replacing
            its data with `data`.
         """
         pass
 
     def fetch_history_get(self, fetch_history_id):
         """Get the fetch_history entry with id `fetch_history_id`.
         """
         raise NotImplementedError('fetch_history_get is deprecated, use '
                                   'origin_visit_get instead.')
 
     def origin_visit_add(self, origin, date=None, *, ts=None):
         """Add an origin_visit for the origin at date with status 'ongoing'.
 
         Args:
             origin (int): visited origin's identifier
             date: timestamp of such visit
 
         Returns:
             dict: dictionary with keys origin and visit where:
 
             - origin: origin's identifier
             - visit: the visit's identifier for the new visit occurrence
 
         """
         if ts is None:
             if date is None:
                 raise TypeError('origin_visit_add expected 2 arguments.')
         else:
             assert date is None
             warnings.warn("argument 'ts' of origin_visit_add was renamed "
                           "to 'date' in v0.0.109.",
                           DeprecationWarning)
             date = ts
 
         origin_id = origin  # TODO: rename the argument
 
         if isinstance(date, str):
             date = dateutil.parser.parse(date)
 
         visit_ret = None
         if origin_id <= len(self._origin_visits):
             # visit ids are in the range [1, +inf[
             visit_id = len(self._origin_visits[origin_id-1]) + 1
             status = 'ongoing'
             visit = {
                 'origin': origin_id,
                 'date': date,
                 'status': status,
                 'snapshot': None,
                 'metadata': None,
                 'visit': visit_id
             }
             self._origin_visits[origin_id-1].append(visit)
             visit_ret = {
                 'origin': origin_id,
                 'visit': visit_id,
             }
 
             if self.journal_writer:
                 origin = self.origin_get([{'id': origin_id}])[0]
                 del origin['id']
                 self.journal_writer.write_addition('origin_visit', {
                     **visit, 'origin': origin})
 
         return visit_ret
 
     def origin_visit_update(self, origin, visit_id, status=None,
                             metadata=None, snapshot=None):
         """Update an origin_visit's status.
 
         Args:
             origin (int): visited origin's identifier
             visit_id (int): visit's identifier
             status: visit's new status
             metadata: data associated to the visit
             snapshot (sha1_git): identifier of the snapshot to add to
                 the visit
 
         Returns:
             None
 
         """
         origin_id = origin  # TODO: rename the argument
 
         try:
             visit = self._origin_visits[origin_id-1][visit_id-1]
         except IndexError:
             raise ValueError('Invalid origin_id or visit_id') from None
         if self.journal_writer:
             origin = self.origin_get([{'id': origin_id}])[0]
             del origin['id']
             self.journal_writer.write_update('origin_visit', {
                 'origin': origin, 'visit': visit_id,
                 'status': status or visit['status'],
                 'date': visit['date'],
                 'metadata': metadata or visit['metadata'],
                 'snapshot': snapshot or visit['snapshot']})
         if origin_id > len(self._origin_visits) or \
            visit_id > len(self._origin_visits[origin_id-1]):
             return
         if status:
             visit['status'] = status
         if metadata:
             visit['metadata'] = metadata
         if snapshot:
             visit['snapshot'] = snapshot
 
     def origin_visit_upsert(self, visits):
         """Add a origin_visits with a specific id and with all its data.
         If there is already an origin_visit with the same
         `(origin_id, visit_id)`, updates it instead of inserting a new one.
 
         Args:
             visits: iterable of dicts with keys:
 
                 origin: Visited Origin id
                 visit: origin visit id
                 date: timestamp of such visit
                 status: Visit's new status
                 metadata: Data associated to the visit
                 snapshot (sha1_git): identifier of the snapshot to add to
                     the visit
         """
         if self.journal_writer:
             for visit in visits:
                 visit = visit.copy()
                 visit['origin'] = self.origin_get([{'id': visit['origin']}])[0]
                 del visit['origin']['id']
                 self.journal_writer.write_addition('origin_visit', visit)
 
         for visit in visits:
             origin_id = visit['origin']
             visit_id = visit['visit']
             if isinstance(visit['date'], str):
                 visit['date'] = dateutil.parser.parse(visit['date'])
             while len(self._origin_visits[origin_id-1]) < visit_id:
                 self._origin_visits[origin_id-1].append(None)
             visit = self._origin_visits[origin_id-1][visit_id-1] = visit
 
     def origin_visit_get(self, origin, last_visit=None, limit=None):
         """Retrieve all the origin's visit's information.
 
         Args:
             origin (int): the origin's identifier
             last_visit (int): visit's id from which listing the next ones,
                 default to None
             limit (int): maximum number of results to return,
                 default to None
 
         Yields:
             List of visits.
 
         """
         if origin <= len(self._origin_visits):
             visits = self._origin_visits[origin-1]
             if last_visit is not None:
                 visits = visits[last_visit:]
             if limit is not None:
                 visits = visits[:limit]
             for visit in visits:
                 if not visit:
                     continue
                 visit_id = visit['visit']
                 yield copy.deepcopy(self._origin_visits[origin-1][visit_id-1])
 
     def origin_visit_get_by(self, origin, visit):
         """Retrieve origin visit's information.
 
         Args:
             origin (int): the origin's identifier
 
         Returns:
             The information on that particular (origin, visit) or None if
             it does not exist
 
         """
         origin_visit = None
         if origin <= len(self._origin_visits) and \
            visit <= len(self._origin_visits[origin-1]):
             origin_visit = self._origin_visits[origin-1][visit-1]
         return copy.deepcopy(origin_visit)
 
     def person_get(self, person):
         """Return the persons identified by their ids.
 
         Args:
             person: array of ids.
 
         Returns:
             The array of persons corresponding of the ids.
 
         """
         for p in person:
             if 0 <= (p - 1) < len(self._persons):
                 yield dict(self._persons[p - 1], id=p)
             else:
                 yield None
 
     def stat_counters(self):
         """compute statistics about the number of tuples in various tables
 
         Returns:
             dict: a dictionary mapping textual labels (e.g., content) to
             integer values (e.g., the number of tuples in table content)
 
         """
         keys = (
             'content',
             'directory',
             'origin',
             'origin_visit',
             'person',
             'release',
             'revision',
             'skipped_content',
             'snapshot'
             )
         stats = {key: 0 for key in keys}
         stats.update(collections.Counter(
             obj_type
             for (obj_type, obj_id)
             in itertools.chain(*self._objects.values())))
         return stats
 
     def refresh_stat_counters(self):
         """Recomputes the statistics for `stat_counters`."""
         pass
 
     def origin_metadata_add(self, origin_id, ts, provider, tool, metadata,
                             db=None, cur=None):
         """ Add an origin_metadata for the origin at ts with provenance and
         metadata.
 
         Args:
             origin_id (int): the origin's id for which the metadata is added
             ts (datetime): timestamp of the found metadata
             provider: id of the provider of metadata (ex:'hal')
             tool: id of the tool used to extract metadata
             metadata (jsonb): the metadata retrieved at the time and location
         """
         if isinstance(ts, str):
             ts = dateutil.parser.parse(ts)
 
         origin_metadata = {
                 'origin_id': origin_id,
                 'discovery_date': ts,
                 'tool_id': tool,
                 'metadata': metadata,
                 'provider_id': provider,
                 }
         self._origin_metadata[origin_id].append(origin_metadata)
         return None
 
     def origin_metadata_get_by(self, origin_id, provider_type=None, db=None,
                                cur=None):
         """Retrieve list of all origin_metadata entries for the origin_id
 
         Args:
             origin_id (int): the unique origin's identifier
             provider_type (str): (optional) type of provider
 
         Returns:
             list of dicts: the origin_metadata dictionary with the keys:
 
             - origin_id (int): origin's identifier
             - discovery_date (datetime): timestamp of discovery
             - tool_id (int): metadata's extracting tool
             - metadata (jsonb)
             - provider_id (int): metadata's provider
             - provider_name (str)
             - provider_type (str)
             - provider_url (str)
 
         """
         metadata = []
         for item in self._origin_metadata[origin_id]:
             item = copy.deepcopy(item)
             provider = self.metadata_provider_get(item['provider_id'])
             for attr in ('name', 'type', 'url'):
                 item['provider_' + attr] = provider[attr]
             metadata.append(item)
         return metadata
 
     def tool_add(self, tools):
         """Add new tools to the storage.
 
         Args:
             tools (iterable of :class:`dict`): Tool information to add to
               storage. Each tool is a :class:`dict` with the following keys:
 
               - name (:class:`str`): name of the tool
               - version (:class:`str`): version of the tool
               - configuration (:class:`dict`): configuration of the tool,
                 must be json-encodable
 
         Returns:
             :class:`dict`: All the tools inserted in storage
             (including the internal ``id``). The order of the list is not
             guaranteed to match the order of the initial list.
 
         """
         inserted = []
         for tool in tools:
             key = self._tool_key(tool)
             assert 'id' not in tool
             record = copy.deepcopy(tool)
             record['id'] = key  # TODO: remove this
             if key not in self._tools:
                 self._tools[key] = record
             inserted.append(copy.deepcopy(self._tools[key]))
 
         return inserted
 
     def tool_get(self, tool):
         """Retrieve tool information.
 
         Args:
             tool (dict): Tool information we want to retrieve from storage.
               The dicts have the same keys as those used in :func:`tool_add`.
 
         Returns:
             dict: The full tool information if it exists (``id`` included),
             None otherwise.
 
         """
         return self._tools.get(self._tool_key(tool))
 
     def metadata_provider_add(self, provider_name, provider_type, provider_url,
                               metadata):
         """Add a metadata provider.
 
         Args:
             provider_name (str): Its name
             provider_type (str): Its type
             provider_url (str): Its URL
             metadata: JSON-encodable object
 
         Returns:
             an identifier of the provider
         """
         provider = {
                 'name': provider_name,
                 'type': provider_type,
                 'url': provider_url,
                 'metadata': metadata,
                 }
         key = self._metadata_provider_key(provider)
         provider['id'] = key
         self._metadata_providers[key] = provider
         return key
 
     def metadata_provider_get(self, provider_id, db=None, cur=None):
         """Get a metadata provider
 
         Args:
             provider_id: Its identifier, as given by `metadata_provider_add`.
 
         Returns:
             dict: same as `metadata_provider_add`;
                   or None if it does not exist.
         """
         return self._metadata_providers.get(provider_id)
 
     def metadata_provider_get_by(self, provider, db=None, cur=None):
         """Get a metadata provider
 
         Args:
             provider_name: Its name
             provider_url: Its URL
 
         Returns:
             dict: same as `metadata_provider_add`;
                   or None if it does not exist.
         """
         key = self._metadata_provider_key({
             'name': provider['provider_name'],
             'url': provider['provider_url']})
         return self._metadata_providers.get(key)
 
     def _origin_id(self, origin):
         origin_id = None
         for stored_origin in self._origins:
             if stored_origin['type'] == origin['type'] and \
                stored_origin['url'] == origin['url']:
                 origin_id = stored_origin['id']
                 break
         return origin_id
 
     def _person_add(self, person):
         """Add a person in storage.
 
         Note: Private method, do not use outside of this class.
 
         Args:
             person: dictionary with keys fullname, name and email.
 
         """
         key = ('person', person['fullname'])
         if key not in self._objects:
             person_id = len(self._persons) + 1
             self._persons.append(dict(person))
             self._objects[key].append(('person', person_id))
         else:
             person_id = self._objects[key][0][1]
             p = next(self.person_get([person_id]))
             person.update(p.items())
         person['id'] = person_id
 
     @staticmethod
     def _content_key(content):
         """A stable key for a content"""
         return tuple(content.get(key) for key in sorted(DEFAULT_ALGORITHMS))
 
     @staticmethod
     def _tool_key(tool):
         return (tool['name'], tool['version'],
                 tuple(sorted(tool['configuration'].items())))
 
     @staticmethod
     def _metadata_provider_key(provider):
         return (provider['name'], provider['url'])
diff --git a/swh/storage/storage.py b/swh/storage/storage.py
index 04b76774..5796ce0b 100644
--- a/swh/storage/storage.py
+++ b/swh/storage/storage.py
@@ -1,1795 +1,1796 @@
 # Copyright (C) 2015-2018  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 
 from collections import defaultdict
 import copy
 from concurrent.futures import ThreadPoolExecutor
 import datetime
 import itertools
 import json
 import warnings
 
 import dateutil.parser
 import psycopg2
 import psycopg2.pool
 
 from . import converters
 from .common import db_transaction_generator, db_transaction
 from .db import Db
 from .exc import StorageDBError
 from .algos import diff
 from .journal_writer import get_journal_writer
 
 from swh.model.hashutil import ALGORITHMS, hash_to_bytes
 from swh.objstorage import get_objstorage
 from swh.objstorage.exc import ObjNotFoundError
 
 
 # Max block size of contents to return
 BULK_BLOCK_CONTENT_LEN_MAX = 10000
 
 EMPTY_SNAPSHOT_ID = hash_to_bytes('1a8893e6a86f444e8be8e7bda6cb34fb1735a00e')
 """Identifier for the empty snapshot"""
 
 
 class Storage():
     """SWH storage proxy, encompassing DB and object storage
 
     """
 
     def __init__(self, db, objstorage, min_pool_conns=1, max_pool_conns=10,
                  journal_writer=None):
         """
         Args:
             db_conn: either a libpq connection string, or a psycopg2 connection
             obj_root: path to the root of the object storage
 
         """
         try:
             if isinstance(db, psycopg2.extensions.connection):
                 self._pool = None
                 self._db = Db(db)
             else:
                 self._pool = psycopg2.pool.ThreadedConnectionPool(
                     min_pool_conns, max_pool_conns, db
                 )
                 self._db = None
         except psycopg2.OperationalError as e:
             raise StorageDBError(e)
 
         self.objstorage = get_objstorage(**objstorage)
         if journal_writer:
             self.journal_writer = get_journal_writer(**journal_writer)
         else:
             self.journal_writer = None
 
     def get_db(self):
         if self._db:
             return self._db
         else:
             return Db.from_pool(self._pool)
 
     def put_db(self, db):
         if db is not self._db:
             db.put_conn()
 
     @db_transaction()
     def check_config(self, *, check_write, db, cur):
         """Check that the storage is configured and ready to go."""
 
         if not self.objstorage.check_config(check_write=check_write):
             return False
 
         # Check permissions on one of the tables
         if check_write:
             check = 'INSERT'
         else:
             check = 'SELECT'
 
         cur.execute(
             "select has_table_privilege(current_user, 'content', %s)",
             (check,)
         )
         return cur.fetchone()[0]
 
     def _content_unique_key(self, hash, db):
         """Given a hash (tuple or dict), return a unique key from the
            aggregation of keys.
 
         """
         keys = db.content_hash_keys
         if isinstance(hash, tuple):
             return hash
         return tuple([hash[k] for k in keys])
 
     def _filter_new_content(self, content, db, cur):
         content_by_status = defaultdict(list)
         for d in content:
             if 'status' not in d:
                 d['status'] = 'visible'
             if 'length' not in d:
                 d['length'] = -1
             content_by_status[d['status']].append(d)
 
         content_with_data = content_by_status['visible']
         content_without_data = content_by_status['absent']
 
         missing_content = set(self.content_missing(content_with_data,
                                                    db=db, cur=cur))
         missing_skipped = set(self._content_unique_key(hashes, db)
                               for hashes in self.skipped_content_missing(
                                   content_without_data, db=db, cur=cur))
 
         content_with_data = [
             cont for cont in content_with_data
             if cont['sha1'] in missing_content]
         content_without_data = [
             cont for cont in content_without_data
             if self._content_unique_key(cont, db) in missing_skipped]
 
         summary = {
             'content:add': len(missing_content),
             'skipped_content:add': len(missing_skipped),
         }
 
         return (content_with_data, content_without_data, summary)
 
     def _content_add_metadata(self, db, cur,
                               content_with_data, content_without_data):
         if content_with_data:
             # create temporary table for metadata injection
             db.mktemp('content', cur)
 
             db.copy_to(content_with_data, 'tmp_content',
                        db.content_add_keys, cur)
 
             # move metadata in place
             try:
                 db.content_add_from_temp(cur)
             except psycopg2.IntegrityError as e:
                 from . import HashCollision
                 if e.diag.sqlstate == '23505' and \
                         e.diag.table_name == 'content':
                     constraint_to_hash_name = {
                         'content_pkey': 'sha1',
                         'content_sha1_git_idx': 'sha1_git',
                         'content_sha256_idx': 'sha256',
                         }
                     colliding_hash_name = constraint_to_hash_name \
                         .get(e.diag.constraint_name)
                     raise HashCollision(colliding_hash_name) from None
                 else:
                     raise
 
         if content_without_data:
             db.mktemp('skipped_content', cur)
             db.copy_to(content_without_data, 'tmp_skipped_content',
                        db.skipped_content_keys, cur)
 
             # move metadata in place
             db.skipped_content_add_from_temp(cur)
 
     @db_transaction()
     def content_add(self, content, db, cur):
         """Add content blobs to the storage
 
         Note: in case of DB errors, objects might have already been added to
         the object storage and will not be removed. Since addition to the
         object storage is idempotent, that should not be a problem.
 
         Args:
             contents (iterable): iterable of dictionaries representing
                 individual pieces of content to add. Each dictionary has the
                 following keys:
 
                 - data (bytes): the actual content
                 - length (int): content length (default: -1)
                 - one key for each checksum algorithm in
                   :data:`swh.model.hashutil.ALGORITHMS`, mapped to the
                   corresponding checksum
                 - status (str): one of visible, hidden, absent
                 - reason (str): if status = absent, the reason why
                 - origin (int): if status = absent, the origin we saw the
                   content in
 
         Raises:
 
             In case of errors, nothing is stored in the db (in the
             objstorage, it could though). The following exceptions can
             occur:
 
             - HashCollision in case of collision
             - Any other exceptions raise by the db
 
         Returns:
             Summary dict with the following key and associated values:
 
                 content:add: New contents added
-                content:bytes:add: Sum of the contents' length data
+                content:add:bytes: Sum of the contents' length data
                 skipped_content:add: New skipped contents (no data) added
         """
         content = [dict(c.items()) for c in content]  # semi-shallow copy
         now = datetime.datetime.now(tz=datetime.timezone.utc)
         for item in content:
             item['ctime'] = now
 
         if self.journal_writer:
             for item in content:
                 if 'data' in item:
                     item = item.copy()
                     del item['data']
                 self.journal_writer.write_addition('content', item)
 
         (content_with_data, content_without_data, summary) = \
             self._filter_new_content(content, db, cur)
 
         def add_to_objstorage():
             """Add to objstorage the new missing_content
 
             Returns:
                 Sum of all the content's data length pushed to the
                 objstorage. Content present twice is only sent once.
 
             """
             content_bytes_added = 0
             data = {}
             for cont in content_with_data:
                 if cont['sha1'] not in data:
                     data[cont['sha1']] = cont['data']
                     content_bytes_added += max(0, cont['length'])
 
             # FIXME: Since we do the filtering anyway now, we might as
             # well make the objstorage's add_batch call return what we
             # want here (real bytes added)... that'd simplify this...
             self.objstorage.add_batch(data)
             return content_bytes_added
 
         with ThreadPoolExecutor(max_workers=1) as executor:
             added_to_objstorage = executor.submit(add_to_objstorage)
 
             self._content_add_metadata(
                 db, cur, content_with_data, content_without_data)
 
             # Wait for objstorage addition before returning from the
             # transaction, bubbling up any exception
             content_bytes_added = added_to_objstorage.result()
 
-        summary['content:bytes:add'] = content_bytes_added
+        summary['content:add:bytes'] = content_bytes_added
         return summary
 
     @db_transaction()
     def content_update(self, content, keys=[], db=None, cur=None):
         """Update content blobs to the storage. Does nothing for unknown
         contents or skipped ones.
 
         Args:
             content (iterable): iterable of dictionaries representing
                 individual pieces of content to update. Each dictionary has the
                 following keys:
 
                 - data (bytes): the actual content
                 - length (int): content length (default: -1)
                 - one key for each checksum algorithm in
                   :data:`swh.model.hashutil.ALGORITHMS`, mapped to the
                   corresponding checksum
                 - status (str): one of visible, hidden, absent
 
             keys (list): List of keys (str) whose values needs an update, e.g.,
                 new hash column
 
         """
         # TODO: Add a check on input keys. How to properly implement
         # this? We don't know yet the new columns.
 
         if self.journal_writer:
             raise NotImplementedError(
                 'content_update is not yet support with a journal_writer.')
 
         db.mktemp('content', cur)
         select_keys = list(set(db.content_get_metadata_keys).union(set(keys)))
         db.copy_to(content, 'tmp_content', select_keys, cur)
         db.content_update_from_temp(keys_to_update=keys,
                                     cur=cur)
 
     @db_transaction()
     def content_add_metadata(self, content, db, cur):
         """Add content metadata to the storage (like `content_add`, but
         without inserting to the objstorage).
 
         Args:
             contents (iterable): iterable of dictionaries representing
                 individual pieces of content to add. Each dictionary has the
                 following keys:
 
                 - length (int): content length (default: -1)
                 - one key for each checksum algorithm in
                   :data:`swh.model.hashutil.ALGORITHMS`, mapped to the
                   corresponding checksum
                 - status (str): one of visible, hidden, absent
                 - reason (str): if status = absent, the reason why
                 - origin (int): if status = absent, the origin we saw the
                   content in
                 - ctime (datetime): time of insertion in the archive
 
         Returns:
             Summary dict with the following key and associated values:
 
                 content:add: New contents added
                 skipped_content:add: New skipped contents (no data) added
         """
         if self.journal_writer:
             for item in content:
                 assert 'data' not in content
                 self.journal_writer.write_addition('content', item)
 
         (content_with_data, content_without_data, summary) = \
             self._filter_new_content(content, db, cur)
 
         self._content_add_metadata(
             db, cur, content_with_data, content_without_data)
 
         return summary
 
     def content_get(self, content):
         """Retrieve in bulk contents and their data.
 
         This generator yields exactly as many items than provided sha1
         identifiers, but callers should not assume this will always be true.
 
         It may also yield `None` values in case an object was not found.
 
         Args:
             content: iterables of sha1
 
         Yields:
             Dict[str, bytes]: Generates streams of contents as dict with their
                 raw data:
 
                 - sha1 (bytes): content id
                 - data (bytes): content's raw data
 
         Raises:
             ValueError in case of too much contents are required.
             cf. BULK_BLOCK_CONTENT_LEN_MAX
 
         """
         # FIXME: Make this method support slicing the `data`.
         if len(content) > BULK_BLOCK_CONTENT_LEN_MAX:
             raise ValueError(
                 "Send at maximum %s contents." % BULK_BLOCK_CONTENT_LEN_MAX)
 
         for obj_id in content:
             try:
                 data = self.objstorage.get(obj_id)
             except ObjNotFoundError:
                 yield None
                 continue
 
             yield {'sha1': obj_id, 'data': data}
 
     @db_transaction()
     def content_get_range(self, start, end, limit=1000, db=None, cur=None):
         """Retrieve contents within range [start, end] bound by limit.
 
         Note that this function may return more than one blob per hash. The
         limit is enforced with multiplicity (ie. two blobs with the same hash
         will count twice toward the limit).
 
         Args:
             **start** (bytes): Starting identifier range (expected smaller
                            than end)
             **end** (bytes): Ending identifier range (expected larger
                              than start)
             **limit** (int): Limit result (default to 1000)
 
         Returns:
             a dict with keys:
             - contents [dict]: iterable of contents in between the range.
             - next (bytes): There remains content in the range
               starting from this next sha1
 
         """
         if limit is None:
             raise ValueError('Development error: limit should not be None')
         contents = []
         next_content = None
         for counter, content_row in enumerate(
                 db.content_get_range(start, end, limit+1, cur)):
             content = dict(zip(db.content_get_metadata_keys, content_row))
             if counter >= limit:
                 # take the last commit for the next page starting from this
                 next_content = content['sha1']
                 break
             contents.append(content)
         return {
             'contents': contents,
             'next': next_content,
         }
 
     @db_transaction_generator(statement_timeout=500)
     def content_get_metadata(self, content, db=None, cur=None):
         """Retrieve content metadata in bulk
 
         Args:
             content: iterable of content identifiers (sha1)
 
         Returns:
             an iterable with content metadata corresponding to the given ids
         """
         for metadata in db.content_get_metadata_from_sha1s(content, cur):
             yield dict(zip(db.content_get_metadata_keys, metadata))
 
     @db_transaction_generator()
     def content_missing(self, content, key_hash='sha1', db=None, cur=None):
         """List content missing from storage
 
         Args:
             content ([dict]): iterable of dictionaries whose keys are
                               either 'length' or an item of
                               :data:`swh.model.hashutil.ALGORITHMS`;
                               mapped to the corresponding checksum
                               (or length).
 
             key_hash (str): name of the column to use as hash id
                             result (default: 'sha1')
 
         Returns:
             iterable ([bytes]): missing content ids (as per the
             key_hash column)
 
         Raises:
             TODO: an exception when we get a hash collision.
 
         """
         keys = db.content_hash_keys
 
         if key_hash not in keys:
             raise ValueError("key_hash should be one of %s" % keys)
 
         key_hash_idx = keys.index(key_hash)
 
         if not content:
             return
 
         for obj in db.content_missing_from_list(content, cur):
             yield obj[key_hash_idx]
 
     @db_transaction_generator()
     def content_missing_per_sha1(self, contents, db=None, cur=None):
         """List content missing from storage based only on sha1.
 
         Args:
             contents: Iterable of sha1 to check for absence.
 
         Returns:
             iterable: missing ids
 
         Raises:
             TODO: an exception when we get a hash collision.
 
         """
         for obj in db.content_missing_per_sha1(contents, cur):
             yield obj[0]
 
     @db_transaction_generator()
     def skipped_content_missing(self, contents, db=None, cur=None):
         """List skipped_content missing from storage
 
         Args:
             content: iterable of dictionaries containing the data for each
                 checksum algorithm.
 
         Returns:
             iterable: missing signatures
 
         """
         for content in db.skipped_content_missing(contents, cur):
             yield dict(zip(db.content_hash_keys, content))
 
     @db_transaction()
     def content_find(self, content, db=None, cur=None):
         """Find a content hash in db.
 
         Args:
             content: a dictionary representing one content hash, mapping
                 checksum algorithm names (see swh.model.hashutil.ALGORITHMS) to
                 checksum values
 
         Returns:
             a triplet (sha1, sha1_git, sha256) if the content exist
             or None otherwise.
 
         Raises:
             ValueError: in case the key of the dictionary is not sha1, sha1_git
                 nor sha256.
 
         """
         if not set(content).intersection(ALGORITHMS):
             raise ValueError('content keys must contain at least one of: '
                              'sha1, sha1_git, sha256, blake2s256')
 
         c = db.content_find(sha1=content.get('sha1'),
                             sha1_git=content.get('sha1_git'),
                             sha256=content.get('sha256'),
                             blake2s256=content.get('blake2s256'),
                             cur=cur)
         if c:
             return dict(zip(db.content_find_cols, c))
         return None
 
     @db_transaction()
     def directory_add(self, directories, db, cur):
         """Add directories to the storage
 
         Args:
             directories (iterable): iterable of dictionaries representing the
                 individual directories to add. Each dict has the following
                 keys:
 
                 - id (sha1_git): the id of the directory to add
                 - entries (list): list of dicts for each entry in the
                       directory.  Each dict has the following keys:
 
                       - name (bytes)
                       - type (one of 'file', 'dir', 'rev'): type of the
                         directory entry (file, directory, revision)
                       - target (sha1_git): id of the object pointed at by the
                         directory entry
                       - perms (int): entry permissions
 
         Returns:
             Summary dict of keys with associated count as values:
 
                 directory:add: Number of directories actually added
 
         """
         summary = {'directory:add': 0}
         if self.journal_writer:
             self.journal_writer.write_additions('directory', directories)
 
         dirs = set()
         dir_entries = {
             'file': defaultdict(list),
             'dir': defaultdict(list),
             'rev': defaultdict(list),
         }
 
         for cur_dir in directories:
             dir_id = cur_dir['id']
             dirs.add(dir_id)
             for src_entry in cur_dir['entries']:
                 entry = src_entry.copy()
                 entry['dir_id'] = dir_id
                 dir_entries[entry['type']][dir_id].append(entry)
 
-        dirs_missing = set(self.directory_missing(dirs))
+        dirs_missing = set(self.directory_missing(dirs, db=db, cur=cur))
         if not dirs_missing:
             return summary
 
         # Copy directory ids
         dirs_missing_dict = ({'id': dir} for dir in dirs_missing)
         db.mktemp('directory', cur)
         db.copy_to(dirs_missing_dict, 'tmp_directory', ['id'], cur)
 
         # Copy entries
         for entry_type, entry_list in dir_entries.items():
             entries = itertools.chain.from_iterable(
                 entries_for_dir
                 for dir_id, entries_for_dir
                 in entry_list.items()
                 if dir_id in dirs_missing)
 
             db.mktemp_dir_entry(entry_type)
 
             db.copy_to(
                 entries,
                 'tmp_directory_entry_%s' % entry_type,
                 ['target', 'name', 'perms', 'dir_id'],
                 cur,
             )
 
         # Do the final copy
         db.directory_add_from_temp(cur)
         summary['directory:add'] = len(dirs_missing)
 
         return summary
 
     @db_transaction_generator()
     def directory_missing(self, directories, db=None, cur=None):
         """List directories missing from storage
 
         Args:
             directories (iterable): an iterable of directory ids
 
         Yields:
             missing directory ids
 
         """
         for obj in db.directory_missing_from_list(directories, cur):
             yield obj[0]
 
     @db_transaction_generator(statement_timeout=20000)
     def directory_ls(self, directory, recursive=False, db=None, cur=None):
         """Get entries for one directory.
 
         Args:
             - directory: the directory to list entries from.
             - recursive: if flag on, this list recursively from this directory.
 
         Returns:
             List of entries for such directory.
 
         If `recursive=True`, names in the path of a dir/file not at the
         root are concatenated with a slash (`/`).
 
         """
         if recursive:
             res_gen = db.directory_walk(directory, cur=cur)
         else:
             res_gen = db.directory_walk_one(directory, cur=cur)
 
         for line in res_gen:
             yield dict(zip(db.directory_ls_cols, line))
 
     @db_transaction(statement_timeout=2000)
     def directory_entry_get_by_path(self, directory, paths, db=None, cur=None):
         """Get the directory entry (either file or dir) from directory with path.
 
         Args:
             - directory: sha1 of the top level directory
             - paths: path to lookup from the top level directory. From left
               (top) to right (bottom).
 
         Returns:
             The corresponding directory entry if found, None otherwise.
 
         """
         res = db.directory_entry_get_by_path(directory, paths, cur)
         if res:
             return dict(zip(db.directory_ls_cols, res))
 
     @db_transaction()
     def revision_add(self, revisions, db, cur):
         """Add revisions to the storage
 
         Args:
             revisions (Iterable[dict]): iterable of dictionaries representing
                 the individual revisions to add. Each dict has the following
                 keys:
 
                 - **id** (:class:`sha1_git`): id of the revision to add
                 - **date** (:class:`dict`): date the revision was written
                 - **committer_date** (:class:`dict`): date the revision got
                   added to the origin
                 - **type** (one of 'git', 'tar'): type of the
                   revision added
                 - **directory** (:class:`sha1_git`): the directory the
                   revision points at
                 - **message** (:class:`bytes`): the message associated with
                   the revision
                 - **author** (:class:`Dict[str, bytes]`): dictionary with
                   keys: name, fullname, email
                 - **committer** (:class:`Dict[str, bytes]`): dictionary with
                   keys: name, fullname, email
                 - **metadata** (:class:`jsonb`): extra information as
                   dictionary
                 - **synthetic** (:class:`bool`): revision's nature (tarball,
                   directory creates synthetic revision`)
                 - **parents** (:class:`list[sha1_git]`): the parents of
                   this revision
 
         date dictionaries have the form defined in :mod:`swh.model`.
 
         Returns:
             Summary dict of keys with associated count as values
 
                 revision:add: New objects actually stored in db
 
         """
         summary = {'revision:add': 0}
 
         if self.journal_writer:
             self.journal_writer.write_additions('revision', revisions)
 
         revisions_missing = set(self.revision_missing(
-            set(revision['id'] for revision in revisions)))
+            set(revision['id'] for revision in revisions),
+            db=db, cur=cur))
 
         if not revisions_missing:
             return summary
 
         db.mktemp_revision(cur)
 
         revisions_filtered = (
             converters.revision_to_db(revision) for revision in revisions
             if revision['id'] in revisions_missing)
 
         parents_filtered = []
 
         db.copy_to(
             revisions_filtered, 'tmp_revision', db.revision_add_cols,
             cur,
             lambda rev: parents_filtered.extend(rev['parents']))
 
         db.revision_add_from_temp(cur)
 
         db.copy_to(parents_filtered, 'revision_history',
                    ['id', 'parent_id', 'parent_rank'], cur)
 
         return {'revision:add': len(revisions_missing)}
 
     @db_transaction_generator()
     def revision_missing(self, revisions, db=None, cur=None):
         """List revisions missing from storage
 
         Args:
             revisions (iterable): revision ids
 
         Yields:
             missing revision ids
 
         """
         if not revisions:
             return
 
         for obj in db.revision_missing_from_list(revisions, cur):
             yield obj[0]
 
     @db_transaction_generator(statement_timeout=1000)
     def revision_get(self, revisions, db=None, cur=None):
         """Get all revisions from storage
 
         Args:
             revisions: an iterable of revision ids
 
         Returns:
             iterable: an iterable of revisions as dictionaries (or None if the
                 revision doesn't exist)
 
         """
         for line in db.revision_get_from_list(revisions, cur):
             data = converters.db_to_revision(
                 dict(zip(db.revision_get_cols, line))
             )
             if not data['type']:
                 yield None
                 continue
             yield data
 
     @db_transaction_generator(statement_timeout=2000)
     def revision_log(self, revisions, limit=None, db=None, cur=None):
         """Fetch revision entry from the given root revisions.
 
         Args:
             revisions: array of root revision to lookup
             limit: limitation on the output result. Default to None.
 
         Yields:
             List of revision log from such revisions root.
 
         """
         for line in db.revision_log(revisions, limit, cur):
             data = converters.db_to_revision(
                 dict(zip(db.revision_get_cols, line))
             )
             if not data['type']:
                 yield None
                 continue
             yield data
 
     @db_transaction_generator(statement_timeout=2000)
     def revision_shortlog(self, revisions, limit=None, db=None, cur=None):
         """Fetch the shortlog for the given revisions
 
         Args:
             revisions: list of root revisions to lookup
             limit: depth limitation for the output
 
         Yields:
             a list of (id, parents) tuples.
 
         """
 
         yield from db.revision_shortlog(revisions, limit, cur)
 
     @db_transaction()
     def release_add(self, releases, db, cur):
         """Add releases to the storage
 
         Args:
             releases (Iterable[dict]): iterable of dictionaries representing
                 the individual releases to add. Each dict has the following
                 keys:
 
                 - **id** (:class:`sha1_git`): id of the release to add
                 - **revision** (:class:`sha1_git`): id of the revision the
                   release points to
                 - **date** (:class:`dict`): the date the release was made
                 - **name** (:class:`bytes`): the name of the release
                 - **comment** (:class:`bytes`): the comment associated with
                   the release
                 - **author** (:class:`Dict[str, bytes]`): dictionary with
                   keys: name, fullname, email
 
         the date dictionary has the form defined in :mod:`swh.model`.
 
         Returns:
             Summary dict of keys with associated count as values
 
                 release:add: New objects contents actually stored in db
 
         """
         summary = {'release:add': 0}
 
         if self.journal_writer:
             self.journal_writer.write_additions('release', releases)
 
         release_ids = set(release['id'] for release in releases)
         releases_missing = set(self.release_missing(release_ids,
                                                     db=db, cur=cur))
 
         if not releases_missing:
             return summary
 
         db.mktemp_release(cur)
 
         releases_missing = list(releases_missing)
 
         releases_filtered = (
             converters.release_to_db(release) for release in releases
             if release['id'] in releases_missing
         )
 
         db.copy_to(releases_filtered, 'tmp_release', db.release_add_cols,
                    cur)
 
         db.release_add_from_temp(cur)
 
         return {'release:add': len(releases_missing)}
 
     @db_transaction_generator()
     def release_missing(self, releases, db=None, cur=None):
         """List releases missing from storage
 
         Args:
             releases: an iterable of release ids
 
         Returns:
             a list of missing release ids
 
         """
         if not releases:
             return
 
         for obj in db.release_missing_from_list(releases, cur):
             yield obj[0]
 
     @db_transaction_generator(statement_timeout=500)
     def release_get(self, releases, db=None, cur=None):
         """Given a list of sha1, return the releases's information
 
         Args:
             releases: list of sha1s
 
         Yields:
             dicts with the same keys as those given to `release_add`
             (or ``None`` if a release does not exist)
 
         """
         for release in db.release_get_from_list(releases, cur):
             data = converters.db_to_release(
                 dict(zip(db.release_get_cols, release))
             )
             yield data if data['target_type'] else None
 
     @db_transaction()
     def snapshot_add(self, snapshots, origin=None, visit=None,
                      db=None, cur=None):
         """Add snapshots to the storage.
 
         Args:
             snapshot ([dict]): the snapshots to add, containing the
               following keys:
 
               - **id** (:class:`bytes`): id of the snapshot
               - **branches** (:class:`dict`): branches the snapshot contains,
                 mapping the branch name (:class:`bytes`) to the branch target,
                 itself a :class:`dict` (or ``None`` if the branch points to an
                 unknown object)
 
                 - **target_type** (:class:`str`): one of ``content``,
                   ``directory``, ``revision``, ``release``,
                   ``snapshot``, ``alias``
                 - **target** (:class:`bytes`): identifier of the target
                   (currently a ``sha1_git`` for all object kinds, or the name
                   of the target branch for aliases)
             origin (int): legacy argument for backward compatibility
             visit (int): legacy argument for backward compatibility
 
         Raises:
             ValueError: if the origin or visit id does not exist.
 
         Returns:
 
             Summary dict of keys with associated count as values
 
                 snapshot:add: Count of object actually stored in db
 
         """
         if origin:
             if not visit:
                 raise TypeError(
                     'snapshot_add expects one argument (or, as a legacy '
                     'behavior, three arguments), not two')
             if isinstance(snapshots, int):
                 # Called by legacy code that uses the new api/client.py
                 (origin_id, visit_id, snapshots) = \
                     (snapshots, origin, [visit])
             else:
                 # Called by legacy code that uses the old api/client.py
                 origin_id = origin
                 visit_id = visit
                 snapshots = [snapshots]
         else:
             # Called by new code that uses the new api/client.py
             origin_id = visit_id = None
 
         created_temp_table = False
 
         count = 0
         for snapshot in snapshots:
             if not db.snapshot_exists(snapshot['id'], cur):
                 if not created_temp_table:
                     db.mktemp_snapshot_branch(cur)
                     created_temp_table = True
 
                 db.copy_to(
                     (
                         {
                             'name': name,
                             'target': info['target'] if info else None,
                             'target_type': (info['target_type']
                                             if info else None),
                         }
                         for name, info in snapshot['branches'].items()
                     ),
                     'tmp_snapshot_branch',
                     ['name', 'target', 'target_type'],
                     cur,
                 )
 
                 if self.journal_writer:
                     self.journal_writer.write_addition('snapshot', snapshot)
 
                 db.snapshot_add(snapshot['id'], cur)
                 count += 1
 
         if visit_id:
             # Legacy API, there can be only one snapshot
             self.origin_visit_update(
                 origin_id, visit_id, snapshot=snapshots[0]['id'],
                 db=db, cur=cur)
 
         return {'snapshot:add': count}
 
     @db_transaction(statement_timeout=2000)
     def snapshot_get(self, snapshot_id, db=None, cur=None):
         """Get the content, possibly partial, of a snapshot with the given id
 
         The branches of the snapshot are iterated in the lexicographical
         order of their names.
 
         .. warning:: At most 1000 branches contained in the snapshot will be
             returned for performance reasons. In order to browse the whole
             set of branches, the method :meth:`snapshot_get_branches`
             should be used instead.
 
         Args:
             snapshot_id (bytes): identifier of the snapshot
         Returns:
             dict: a dict with three keys:
                 * **id**: identifier of the snapshot
                 * **branches**: a dict of branches contained in the snapshot
                   whose keys are the branches' names.
                 * **next_branch**: the name of the first branch not returned
                   or :const:`None` if the snapshot has less than 1000
                   branches.
         """
 
         return self.snapshot_get_branches(snapshot_id, db=db, cur=cur)
 
     @db_transaction(statement_timeout=2000)
     def snapshot_get_by_origin_visit(self, origin, visit, db=None, cur=None):
         """Get the content, possibly partial, of a snapshot for the given origin visit
 
         The branches of the snapshot are iterated in the lexicographical
         order of their names.
 
         .. warning:: At most 1000 branches contained in the snapshot will be
             returned for performance reasons. In order to browse the whole
             set of branches, the method :meth:`snapshot_get_branches`
             should be used instead.
 
         Args:
             origin (int): the origin identifier
             visit (int): the visit identifier
         Returns:
             dict: None if the snapshot does not exist;
               a dict with three keys otherwise:
                 * **id**: identifier of the snapshot
                 * **branches**: a dict of branches contained in the snapshot
                   whose keys are the branches' names.
                 * **next_branch**: the name of the first branch not returned
                   or :const:`None` if the snapshot has less than 1000
                   branches.
 
         """
         snapshot_id = db.snapshot_get_by_origin_visit(origin, visit, cur)
 
         if snapshot_id:
             return self.snapshot_get(snapshot_id, db=db, cur=cur)
 
         return None
 
     @db_transaction(statement_timeout=4000)
     def snapshot_get_latest(self, origin, allowed_statuses=None, db=None,
                             cur=None):
         """Get the content, possibly partial, of the latest snapshot for the
         given origin, optionally only from visits that have one of the given
         allowed_statuses
 
         The branches of the snapshot are iterated in the lexicographical
         order of their names.
 
         .. warning:: At most 1000 branches contained in the snapshot will be
             returned for performance reasons. In order to browse the whole
             set of branches, the method :meth:`snapshot_get_branches`
             should be used instead.
 
         Args:
             origin (int): the origin identifier
             allowed_statuses (list of str): list of visit statuses considered
                 to find the latest snapshot for the visit. For instance,
                 ``allowed_statuses=['full']`` will only consider visits that
                 have successfully run to completion.
         Returns:
             dict: a dict with three keys:
                 * **id**: identifier of the snapshot
                 * **branches**: a dict of branches contained in the snapshot
                   whose keys are the branches' names.
                 * **next_branch**: the name of the first branch not returned
                   or :const:`None` if the snapshot has less than 1000
                   branches.
         """
         origin_visit = db.origin_visit_get_latest_snapshot(
             origin, allowed_statuses=allowed_statuses, cur=cur)
         if origin_visit:
             origin_visit = dict(zip(db.origin_visit_get_cols, origin_visit))
             return self.snapshot_get(origin_visit['snapshot'], db=db, cur=cur)
 
     @db_transaction(statement_timeout=2000)
     def snapshot_count_branches(self, snapshot_id, db=None, cur=None):
         """Count the number of branches in the snapshot with the given id
 
         Args:
             snapshot_id (bytes): identifier of the snapshot
 
         Returns:
             dict: A dict whose keys are the target types of branches and
             values their corresponding amount
         """
         return dict([bc for bc in
                      db.snapshot_count_branches(snapshot_id, cur)])
 
     @db_transaction(statement_timeout=2000)
     def snapshot_get_branches(self, snapshot_id, branches_from=b'',
                               branches_count=1000, target_types=None,
                               db=None, cur=None):
         """Get the content, possibly partial, of a snapshot with the given id
 
         The branches of the snapshot are iterated in the lexicographical
         order of their names.
 
         Args:
             snapshot_id (bytes): identifier of the snapshot
             branches_from (bytes): optional parameter used to skip branches
                 whose name is lesser than it before returning them
             branches_count (int): optional parameter used to restrain
                 the amount of returned branches
             target_types (list): optional parameter used to filter the
                 target types of branch to return (possible values that can be
                 contained in that list are `'content', 'directory',
                 'revision', 'release', 'snapshot', 'alias'`)
         Returns:
             dict: None if the snapshot does not exist;
               a dict with three keys otherwise:
                 * **id**: identifier of the snapshot
                 * **branches**: a dict of branches contained in the snapshot
                   whose keys are the branches' names.
                 * **next_branch**: the name of the first branch not returned
                   or :const:`None` if the snapshot has less than
                   `branches_count` branches after `branches_from` included.
         """
         if snapshot_id == EMPTY_SNAPSHOT_ID:
             return {
                 'id': snapshot_id,
                 'branches': {},
                 'next_branch': None,
             }
 
         branches = {}
         next_branch = None
 
         fetched_branches = list(db.snapshot_get_by_id(
             snapshot_id, branches_from=branches_from,
             branches_count=branches_count+1, target_types=target_types,
             cur=cur,
         ))
         for branch in fetched_branches[:branches_count]:
             branch = dict(zip(db.snapshot_get_cols, branch))
             del branch['snapshot_id']
             name = branch.pop('name')
             if branch == {'target': None, 'target_type': None}:
                 branch = None
             branches[name] = branch
 
         if len(fetched_branches) > branches_count:
             branch = dict(zip(db.snapshot_get_cols, fetched_branches[-1]))
             next_branch = branch['name']
 
         if branches:
             return {
                 'id': snapshot_id,
                 'branches': branches,
                 'next_branch': next_branch,
             }
 
         return None
 
     @db_transaction()
     def origin_visit_add(self, origin, date=None, db=None, cur=None, *,
                          ts=None):
         """Add an origin_visit for the origin at ts with status 'ongoing'.
 
         Args:
             origin: Visited Origin id
             date: timestamp of such visit
 
         Returns:
             dict: dictionary with keys origin and visit where:
 
             - origin: origin identifier
             - visit: the visit identifier for the new visit occurrence
 
         """
         if ts is None:
             if date is None:
                 raise TypeError('origin_visit_add expected 2 arguments.')
         else:
             assert date is None
             warnings.warn("argument 'ts' of origin_visit_add was renamed "
                           "to 'date' in v0.0.109.",
                           DeprecationWarning)
             date = ts
 
         origin_id = origin  # TODO: rename the argument
 
         if isinstance(date, str):
             date = dateutil.parser.parse(date)
 
         visit_id = db.origin_visit_add(origin_id, date, cur)
 
         if self.journal_writer:
             # We can write to the journal only after inserting to the
             # DB, because we want the id of the visit
             origin = self.origin_get([{'id': origin_id}], db=db, cur=cur)[0]
             del origin['id']
             self.journal_writer.write_addition('origin_visit', {
                 'origin': origin, 'date': date, 'visit': visit_id,
                 'status': 'ongoing', 'metadata': None, 'snapshot': None})
 
         return {
             'origin': origin_id,
             'visit': visit_id,
         }
 
     @db_transaction()
     def origin_visit_update(self, origin, visit_id, status=None,
                             metadata=None, snapshot=None,
                             db=None, cur=None):
         """Update an origin_visit's status.
 
         Args:
             origin: Visited Origin id
             visit_id: Visit's id
             status: Visit's new status
             metadata: Data associated to the visit
             snapshot (sha1_git): identifier of the snapshot to add to
                 the visit
 
         Returns:
             None
 
         """
         origin_id = origin  # TODO: rename the argument
 
         visit = db.origin_visit_get(origin_id, visit_id, cur=cur)
 
         if not visit:
             raise ValueError('Invalid visit_id for this origin.')
 
         visit = dict(zip(db.origin_visit_get_cols, visit))
 
         updates = {}
         if status and status != visit['status']:
             updates['status'] = status
         if metadata and metadata != visit['metadata']:
             updates['metadata'] = metadata
         if snapshot and snapshot != visit['snapshot']:
             updates['snapshot'] = snapshot
 
         if updates:
             if self.journal_writer:
                 origin = self.origin_get(
                     [{'id': origin_id}], db=db, cur=cur)[0]
                 del origin['id']
                 self.journal_writer.write_update('origin_visit', {
                     **visit, **updates, 'origin': origin})
 
             db.origin_visit_update(origin_id, visit_id, updates, cur)
 
     @db_transaction()
     def origin_visit_upsert(self, visits, db=None, cur=None):
         """Add a origin_visits with a specific id and with all its data.
         If there is already an origin_visit with the same
         `(origin_id, visit_id)`, overwrites it.
 
         Args:
             visits: iterable of dicts with keys:
 
                 origin: Visited Origin id
                 visit: origin visit id
                 date: timestamp of such visit
                 status: Visit's new status
                 metadata: Data associated to the visit
                 snapshot (sha1_git): identifier of the snapshot to add to
                     the visit
         """
         if self.journal_writer:
             for visit in visits:
                 visit = visit.copy()
                 visit['origin'] = self.origin_get(
                     [{'id': visit['origin']}], db=db, cur=cur)[0]
                 del visit['origin']['id']
                 self.journal_writer.write_addition('origin_visit', visit)
 
         for visit in visits:
             # TODO: upsert them all in a single query
             db.origin_visit_upsert(**visit, cur=cur)
 
     @db_transaction_generator(statement_timeout=500)
     def origin_visit_get(self, origin, last_visit=None, limit=None, db=None,
                          cur=None):
         """Retrieve all the origin's visit's information.
 
         Args:
             origin (int): The occurrence's origin (identifier).
             last_visit: Starting point from which listing the next visits
                 Default to None
             limit (int): Number of results to return from the last visit.
                 Default to None
 
         Yields:
             List of visits.
 
         """
         for line in db.origin_visit_get_all(
                 origin, last_visit=last_visit, limit=limit, cur=cur):
             data = dict(zip(db.origin_visit_get_cols, line))
             yield data
 
     @db_transaction(statement_timeout=500)
     def origin_visit_get_by(self, origin, visit, db=None, cur=None):
         """Retrieve origin visit's information.
 
         Args:
             origin: The occurrence's origin (identifier).
 
         Returns:
             The information on that particular (origin, visit) or None if
             it does not exist
 
         """
         ori_visit = db.origin_visit_get(origin, visit, cur)
         if not ori_visit:
             return None
 
         return dict(zip(db.origin_visit_get_cols, ori_visit))
 
     @db_transaction(statement_timeout=2000)
     def object_find_by_sha1_git(self, ids, db=None, cur=None):
         """Return the objects found with the given ids.
 
         Args:
             ids: a generator of sha1_gits
 
         Returns:
             dict: a mapping from id to the list of objects found. Each object
             found is itself a dict with keys:
 
             - sha1_git: the input id
             - type: the type of object found
             - id: the id of the object found
             - object_id: the numeric id of the object found.
 
         """
         ret = {id: [] for id in ids}
 
         for retval in db.object_find_by_sha1_git(ids, cur=cur):
             if retval[1]:
                 ret[retval[0]].append(dict(zip(db.object_find_by_sha1_git_cols,
                                                retval)))
 
         return ret
 
     origin_keys = ['id', 'type', 'url']
 
     @db_transaction(statement_timeout=500)
     def origin_get(self, origins, db=None, cur=None):
         """Return origins, either all identified by their ids or all
         identified by tuples (type, url).
 
         Args:
             origin: a list of dictionaries representing the individual
                 origins to find.
                 These dicts have either the keys type and url:
 
                 - type (FIXME: enum TBD): the origin type ('git', 'wget', ...)
                 - url (bytes): the url the origin points to
 
                 or the id:
 
                 - id: the origin id
 
         Returns:
             dict: the origin dictionary with the keys:
 
             - id: origin's id
             - type: origin's type
             - url: origin's url
 
         Raises:
             ValueError: if the keys does not match (url and type) nor id.
 
         """
         if isinstance(origins, dict):
             # Old API
             return_single = True
             origins = [origins]
         elif len(origins) == 0:
             return []
         else:
             return_single = False
 
         origin_ids = [origin.get('id') for origin in origins]
         origin_types_and_urls = [(origin.get('type'), origin.get('url'))
                                  for origin in origins]
         if any(origin_ids):
             # Lookup per ID
             if all(origin_ids):
                 results = db.origin_get(origin_ids, cur)
             else:
                 raise ValueError(
                     'Either all origins or none at all should have an "id".')
         elif any(type_ and url for (type_, url) in origin_types_and_urls):
             # Lookup per type + URL
             if all(type_ and url for (type_, url) in origin_types_and_urls):
                 results = db.origin_get_with(origin_types_and_urls, cur)
             else:
                 raise ValueError(
                     'Either all origins or none at all should have a '
                     '"type" and an "url".')
         else:  # unsupported lookup
             raise ValueError('Origin must have either id or (type and url).')
 
         results = [dict(zip(self.origin_keys, result))
                    for result in results]
         if return_single:
             assert len(results) == 1
             if results[0]['id'] is not None:
                 return results[0]
             else:
                 return None
         else:
             return [None if res['id'] is None else res for res in results]
 
     @db_transaction_generator()
     def origin_get_range(self, origin_from=1, origin_count=100,
                          db=None, cur=None):
         """Retrieve ``origin_count`` origins whose ids are greater
         or equal than ``origin_from``.
 
         Origins are sorted by id before retrieving them.
 
         Args:
             origin_from (int): the minimum id of origins to retrieve
             origin_count (int): the maximum number of origins to retrieve
 
         Yields:
             dicts containing origin information as returned
             by :meth:`swh.storage.storage.Storage.origin_get`.
         """
         for origin in db.origin_get_range(origin_from, origin_count, cur):
             yield dict(zip(self.origin_keys, origin))
 
     @db_transaction_generator()
     def origin_search(self, url_pattern, offset=0, limit=50,
                       regexp=False, with_visit=False, db=None, cur=None):
         """Search for origins whose urls contain a provided string pattern
         or match a provided regular expression.
         The search is performed in a case insensitive way.
 
         Args:
             url_pattern (str): the string pattern to search for in origin urls
             offset (int): number of found origins to skip before returning
                 results
             limit (int): the maximum number of found origins to return
             regexp (bool): if True, consider the provided pattern as a regular
                 expression and return origins whose urls match it
             with_visit (bool): if True, filter out origins with no visit
 
         Yields:
             dicts containing origin information as returned
             by :meth:`swh.storage.storage.Storage.origin_get`.
         """
         for origin in db.origin_search(url_pattern, offset, limit,
                                        regexp, with_visit, cur):
             yield dict(zip(self.origin_keys, origin))
 
     @db_transaction()
     def origin_count(self, url_pattern, regexp=False,
                      with_visit=False, db=None, cur=None):
         """Count origins whose urls contain a provided string pattern
         or match a provided regular expression.
         The pattern search in origin urls is performed in a case insensitive
         way.
 
         Args:
             url_pattern (str): the string pattern to search for in origin urls
             regexp (bool): if True, consider the provided pattern as a regular
                 expression and return origins whose urls match it
             with_visit (bool): if True, filter out origins with no visit
 
         Returns:
             int: The number of origins matching the search criterion.
         """
         return db.origin_count(url_pattern, regexp, with_visit, cur)
 
     @db_transaction_generator(statement_timeout=500)
     def person_get(self, person, db=None, cur=None):
         """Return the persons identified by their ids.
 
         Args:
             person: array of ids.
 
         Returns:
             The array of persons corresponding of the ids.
 
         """
         for person in db.person_get(person):
             yield dict(zip(db.person_get_cols, person))
 
     @db_transaction()
     def origin_add(self, origins, db=None, cur=None):
         """Add origins to the storage
 
         Args:
             origins: list of dictionaries representing the individual origins,
                 with the following keys:
 
                 - type: the origin type ('git', 'svn', 'deb', ...)
                 - url (bytes): the url the origin points to
 
         Returns:
             list: given origins as dict updated with their id
 
         """
         origins = copy.deepcopy(origins)
         for origin in origins:
             origin['id'] = self.origin_add_one(origin, db=db, cur=cur)
 
         return origins
 
     @db_transaction()
     def origin_add_one(self, origin, db=None, cur=None):
         """Add origin to the storage
 
         Args:
             origin: dictionary representing the individual origin to add. This
                 dict has the following keys:
 
                 - type (FIXME: enum TBD): the origin type ('git', 'wget', ...)
                 - url (bytes): the url the origin points to
 
         Returns:
             the id of the added origin, or of the identical one that already
             exists.
 
         """
         origin_id = list(db.origin_get_with(
             [(origin['type'], origin['url'])], cur))[0][0]
         if origin_id:
             return origin_id
 
         if self.journal_writer:
             self.journal_writer.write_addition('origin', origin)
 
         return db.origin_add(origin['type'], origin['url'], cur)
 
     @db_transaction()
     def fetch_history_start(self, origin_id, db=None, cur=None):
         """Add an entry for origin origin_id in fetch_history. Returns the id
         of the added fetch_history entry
         """
         fetch_history = {
             'origin': origin_id,
             'date': datetime.datetime.now(tz=datetime.timezone.utc),
         }
 
         return db.create_fetch_history(fetch_history, cur)
 
     @db_transaction()
     def fetch_history_end(self, fetch_history_id, data, db=None, cur=None):
         """Close the fetch_history entry with id `fetch_history_id`, replacing
            its data with `data`.
         """
         now = datetime.datetime.now(tz=datetime.timezone.utc)
         fetch_history = db.get_fetch_history(fetch_history_id, cur)
 
         if not fetch_history:
             raise ValueError('No fetch_history with id %d' % fetch_history_id)
 
         fetch_history['duration'] = now - fetch_history['date']
 
         fetch_history.update(data)
 
         db.update_fetch_history(fetch_history, cur)
 
     @db_transaction()
     def fetch_history_get(self, fetch_history_id, db=None, cur=None):
         """Get the fetch_history entry with id `fetch_history_id`.
         """
         return db.get_fetch_history(fetch_history_id, cur)
 
     @db_transaction(statement_timeout=500)
     def stat_counters(self, db=None, cur=None):
         """compute statistics about the number of tuples in various tables
 
         Returns:
             dict: a dictionary mapping textual labels (e.g., content) to
             integer values (e.g., the number of tuples in table content)
 
         """
         return {k: v for (k, v) in db.stat_counters()}
 
     @db_transaction()
     def refresh_stat_counters(self, db=None, cur=None):
         """Recomputes the statistics for `stat_counters`."""
         keys = [
             'content',
             'directory',
             'directory_entry_dir',
             'directory_entry_file',
             'directory_entry_rev',
             'origin',
             'origin_visit',
             'person',
             'release',
             'revision',
             'revision_history',
             'skipped_content',
             'snapshot']
 
         for key in keys:
             cur.execute('select * from swh_update_counter(%s)', (key,))
 
     @db_transaction()
     def origin_metadata_add(self, origin_id, ts, provider, tool, metadata,
                             db=None, cur=None):
         """ Add an origin_metadata for the origin at ts with provenance and
         metadata.
 
         Args:
             origin_id (int): the origin's id for which the metadata is added
             ts (datetime): timestamp of the found metadata
             provider (int): the provider of metadata (ex:'hal')
             tool (int): tool used to extract metadata
             metadata (jsonb): the metadata retrieved at the time and location
 
         Returns:
             id (int): the origin_metadata unique id
         """
         if isinstance(ts, str):
             ts = dateutil.parser.parse(ts)
 
         return db.origin_metadata_add(origin_id, ts, provider, tool,
                                       metadata, cur)
 
     @db_transaction_generator(statement_timeout=500)
     def origin_metadata_get_by(self, origin_id, provider_type=None, db=None,
                                cur=None):
         """Retrieve list of all origin_metadata entries for the origin_id
 
         Args:
             origin_id (int): the unique origin identifier
             provider_type (str): (optional) type of provider
 
         Returns:
             list of dicts: the origin_metadata dictionary with the keys:
 
             - origin_id (int): origin's id
             - discovery_date (datetime): timestamp of discovery
             - tool_id (int): metadata's extracting tool
             - metadata (jsonb)
             - provider_id (int): metadata's provider
             - provider_name (str)
             - provider_type (str)
             - provider_url (str)
 
         """
         for line in db.origin_metadata_get_by(origin_id, provider_type, cur):
             yield dict(zip(db.origin_metadata_get_cols, line))
 
     @db_transaction()
     def tool_add(self, tools, db=None, cur=None):
         """Add new tools to the storage.
 
         Args:
             tools (iterable of :class:`dict`): Tool information to add to
               storage. Each tool is a :class:`dict` with the following keys:
 
               - name (:class:`str`): name of the tool
               - version (:class:`str`): version of the tool
               - configuration (:class:`dict`): configuration of the tool,
                 must be json-encodable
 
         Returns:
             :class:`dict`: All the tools inserted in storage
             (including the internal ``id``). The order of the list is not
             guaranteed to match the order of the initial list.
 
         """
         db.mktemp_tool(cur)
         db.copy_to(tools, 'tmp_tool',
                    ['name', 'version', 'configuration'],
                    cur)
 
         tools = db.tool_add_from_temp(cur)
         return [dict(zip(db.tool_cols, line)) for line in tools]
 
     @db_transaction(statement_timeout=500)
     def tool_get(self, tool, db=None, cur=None):
         """Retrieve tool information.
 
         Args:
             tool (dict): Tool information we want to retrieve from storage.
               The dicts have the same keys as those used in :func:`tool_add`.
 
         Returns:
             dict: The full tool information if it exists (``id`` included),
             None otherwise.
 
         """
         tool_conf = tool['configuration']
         if isinstance(tool_conf, dict):
             tool_conf = json.dumps(tool_conf)
 
         idx = db.tool_get(tool['name'],
                           tool['version'],
                           tool_conf)
         if not idx:
             return None
         return dict(zip(db.tool_cols, idx))
 
     @db_transaction()
     def metadata_provider_add(self, provider_name, provider_type, provider_url,
                               metadata, db=None, cur=None):
         """Add a metadata provider.
 
         Args:
             provider_name (str): Its name
             provider_type (str): Its type (eg. `'deposit-client'`)
             provider_url (str): Its URL
             metadata: JSON-encodable object
 
         Returns:
             int: an identifier of the provider
         """
         return db.metadata_provider_add(provider_name, provider_type,
                                         provider_url, metadata, cur)
 
     @db_transaction()
     def metadata_provider_get(self, provider_id, db=None, cur=None):
         """Get a metadata provider
 
         Args:
             provider_id: Its identifier, as given by `metadata_provider_add`.
 
         Returns:
             dict: same as `metadata_provider_add`;
                   or None if it does not exist.
         """
         result = db.metadata_provider_get(provider_id)
         if not result:
             return None
         return dict(zip(db.metadata_provider_cols, result))
 
     @db_transaction()
     def metadata_provider_get_by(self, provider, db=None, cur=None):
         """Get a metadata provider
 
         Args:
             provider (dict): A dictionary with keys:
                 * provider_name: Its name
                 * provider_url: Its URL
 
         Returns:
             dict: same as `metadata_provider_add`;
                   or None if it does not exist.
         """
         result = db.metadata_provider_get_by(provider['provider_name'],
                                              provider['provider_url'])
         if not result:
             return None
         return dict(zip(db.metadata_provider_cols, result))
 
     def diff_directories(self, from_dir, to_dir, track_renaming=False):
         """Compute the list of file changes introduced between two arbitrary
         directories (insertion / deletion / modification / renaming of files).
 
         Args:
             from_dir (bytes): identifier of the directory to compare from
             to_dir (bytes): identifier of the directory to compare to
             track_renaming (bool): whether or not to track files renaming
 
         Returns:
             A list of dict describing the introduced file changes
             (see :func:`swh.storage.algos.diff.diff_directories`
             for more details).
         """
         return diff.diff_directories(self, from_dir, to_dir, track_renaming)
 
     def diff_revisions(self, from_rev, to_rev, track_renaming=False):
         """Compute the list of file changes introduced between two arbitrary
         revisions (insertion / deletion / modification / renaming of files).
 
         Args:
             from_rev (bytes): identifier of the revision to compare from
             to_rev (bytes): identifier of the revision to compare to
             track_renaming (bool): whether or not to track files renaming
 
         Returns:
             A list of dict describing the introduced file changes
             (see :func:`swh.storage.algos.diff.diff_directories`
             for more details).
         """
         return diff.diff_revisions(self, from_rev, to_rev, track_renaming)
 
     def diff_revision(self, revision, track_renaming=False):
         """Compute the list of file changes introduced by a specific revision
         (insertion / deletion / modification / renaming of files) by comparing
         it against its first parent.
 
         Args:
             revision (bytes): identifier of the revision from which to
                 compute the list of files changes
             track_renaming (bool): whether or not to track files renaming
 
         Returns:
             A list of dict describing the introduced file changes
             (see :func:`swh.storage.algos.diff.diff_directories`
             for more details).
         """
         return diff.diff_revision(self, revision, track_renaming)
diff --git a/swh/storage/tests/test_storage.py b/swh/storage/tests/test_storage.py
index a08e1da7..2783906e 100644
--- a/swh/storage/tests/test_storage.py
+++ b/swh/storage/tests/test_storage.py
@@ -1,3212 +1,3212 @@
 # Copyright (C) 2015-2019  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
 import copy
 import datetime
 import itertools
 import random
 import unittest
 from collections import defaultdict
 from unittest.mock import Mock, patch
 
 import pytest
 
 from hypothesis import given, strategies
 
 from swh.model import from_disk, identifiers
 from swh.model.hashutil import hash_to_bytes
 from swh.model.hypothesis_strategies import origins, objects
 from swh.storage.tests.storage_testing import StorageTestFixture
 from swh.storage import HashCollision
 
 from .generate_data_test import gen_contents
 
 
 @pytest.mark.db
 class StorageTestDbFixture(StorageTestFixture):
     def setUp(self):
         super().setUp()
 
         db = self.test_db[self.TEST_DB_NAME]
         self.conn = db.conn
         self.cursor = db.cursor
 
         self.maxDiff = None
 
     def tearDown(self):
         self.reset_storage_tables()
         super().tearDown()
 
 
 class TestStorageData:
     def setUp(self):
         super().setUp()
 
         self.cont = {
             'data': b'42\n',
             'length': 3,
             'sha1': hash_to_bytes(
                 '34973274ccef6ab4dfaaf86599792fa9c3fe4689'),
             'sha1_git': hash_to_bytes(
                 'd81cc0710eb6cf9efd5b920a8453e1e07157b6cd'),
             'sha256': hash_to_bytes(
                 '673650f936cb3b0a2f93ce09d81be107'
                 '48b1b203c19e8176b4eefc1964a0cf3a'),
             'blake2s256': hash_to_bytes('d5fe1939576527e42cfd76a9455a2'
                                         '432fe7f56669564577dd93c4280e76d661d'),
             'status': 'visible',
         }
 
         self.cont2 = {
             'data': b'4242\n',
             'length': 5,
             'sha1': hash_to_bytes(
                 '61c2b3a30496d329e21af70dd2d7e097046d07b7'),
             'sha1_git': hash_to_bytes(
                 '36fade77193cb6d2bd826161a0979d64c28ab4fa'),
             'sha256': hash_to_bytes(
                 '859f0b154fdb2d630f45e1ecae4a8629'
                 '15435e663248bb8461d914696fc047cd'),
             'blake2s256': hash_to_bytes('849c20fad132b7c2d62c15de310adfe87be'
                                         '94a379941bed295e8141c6219810d'),
             'status': 'visible',
         }
 
         self.cont3 = {
             'data': b'424242\n',
             'length': 7,
             'sha1': hash_to_bytes(
                 '3e21cc4942a4234c9e5edd8a9cacd1670fe59f13'),
             'sha1_git': hash_to_bytes(
                 'c932c7649c6dfa4b82327d121215116909eb3bea'),
             'sha256': hash_to_bytes(
                 '92fb72daf8c6818288a35137b72155f5'
                 '07e5de8d892712ab96277aaed8cf8a36'),
             'blake2s256': hash_to_bytes('76d0346f44e5a27f6bafdd9c2befd304af'
                                         'f83780f93121d801ab6a1d4769db11'),
             'status': 'visible',
         }
 
         self.missing_cont = {
             'data': b'missing\n',
             'length': 8,
             'sha1': hash_to_bytes(
                 'f9c24e2abb82063a3ba2c44efd2d3c797f28ac90'),
             'sha1_git': hash_to_bytes(
                 '33e45d56f88993aae6a0198013efa80716fd8919'),
             'sha256': hash_to_bytes(
                 '6bbd052ab054ef222c1c87be60cd191a'
                 'ddedd24cc882d1f5f7f7be61dc61bb3a'),
             'blake2s256': hash_to_bytes('306856b8fd879edb7b6f1aeaaf8db9bbecc9'
                                         '93cd7f776c333ac3a782fa5c6eba'),
             'status': 'absent',
         }
 
         self.skipped_cont = {
             'length': 1024 * 1024 * 200,
             'sha1_git': hash_to_bytes(
                 '33e45d56f88993aae6a0198013efa80716fd8920'),
             'sha1': hash_to_bytes(
                 '43e45d56f88993aae6a0198013efa80716fd8920'),
             'sha256': hash_to_bytes(
                 '7bbd052ab054ef222c1c87be60cd191a'
                 'ddedd24cc882d1f5f7f7be61dc61bb3a'),
             'blake2s256': hash_to_bytes(
                 'ade18b1adecb33f891ca36664da676e1'
                 '2c772cc193778aac9a137b8dc5834b9b'),
             'reason': 'Content too long',
             'status': 'absent',
         }
 
         self.skipped_cont2 = {
             'length': 1024 * 1024 * 300,
             'sha1_git': hash_to_bytes(
                 '44e45d56f88993aae6a0198013efa80716fd8921'),
             'sha1': hash_to_bytes(
                 '54e45d56f88993aae6a0198013efa80716fd8920'),
             'sha256': hash_to_bytes(
                 '8cbd052ab054ef222c1c87be60cd191a'
                 'ddedd24cc882d1f5f7f7be61dc61bb3a'),
             'blake2s256': hash_to_bytes(
                 '9ce18b1adecb33f891ca36664da676e1'
                 '2c772cc193778aac9a137b8dc5834b9b'),
             'reason': 'Content too long',
             'status': 'absent',
         }
 
         self.dir = {
             'id': b'4\x013\x422\x531\x000\xf51\xe62\xa73\xff7\xc3\xa90',
             'entries': [
                 {
                     'name': b'foo',
                     'type': 'file',
                     'target': self.cont['sha1_git'],
                     'perms': from_disk.DentryPerms.content,
                 },
                 {
                     'name': b'bar\xc3',
                     'type': 'dir',
                     'target': b'12345678901234567890',
                     'perms': from_disk.DentryPerms.directory,
                 },
             ],
         }
 
         self.dir2 = {
             'id': b'4\x013\x422\x531\x000\xf51\xe62\xa73\xff7\xc3\xa95',
             'entries': [
                 {
                     'name': b'oof',
                     'type': 'file',
                     'target': self.cont2['sha1_git'],
                     'perms': from_disk.DentryPerms.content,
                 }
             ],
         }
 
         self.dir3 = {
             'id': hash_to_bytes('33e45d56f88993aae6a0198013efa80716fd8921'),
             'entries': [
                 {
                     'name': b'foo',
                     'type': 'file',
                     'target': self.cont['sha1_git'],
                     'perms': from_disk.DentryPerms.content,
                 },
                 {
                     'name': b'subdir',
                     'type': 'dir',
                     'target': self.dir['id'],
                     'perms': from_disk.DentryPerms.directory,
                 },
                 {
                     'name': b'hello',
                     'type': 'file',
                     'target': b'12345678901234567890',
                     'perms': from_disk.DentryPerms.content,
                 },
 
             ],
         }
 
         self.minus_offset = datetime.timezone(datetime.timedelta(minutes=-120))
         self.plus_offset = datetime.timezone(datetime.timedelta(minutes=120))
 
         self.revision = {
             'id': b'56789012345678901234',
             'message': b'hello',
             'author': {
                 'name': b'Nicolas Dandrimont',
                 'email': b'nicolas@example.com',
                 'fullname': b'Nicolas Dandrimont <nicolas@example.com> ',
             },
             'date': {
                 'timestamp': 1234567890,
                 'offset': 120,
                 'negative_utc': None,
             },
             'committer': {
                 'name': b'St\xc3fano Zacchiroli',
                 'email': b'stefano@example.com',
                 'fullname': b'St\xc3fano Zacchiroli <stefano@example.com>'
             },
             'committer_date': {
                 'timestamp': 1123456789,
                 'offset': 0,
                 'negative_utc': True,
             },
             'parents': [b'01234567890123456789', b'23434512345123456789'],
             'type': 'git',
             'directory': self.dir['id'],
             'metadata': {
                 'checksums': {
                     'sha1': 'tarball-sha1',
                     'sha256': 'tarball-sha256',
                 },
                 'signed-off-by': 'some-dude',
                 'extra_headers': [
                     ['gpgsig', b'test123'],
                     ['mergetags', [b'foo\\bar', b'\x22\xaf\x89\x80\x01\x00']],
                 ],
             },
             'synthetic': True
         }
 
         self.revision2 = {
             'id': b'87659012345678904321',
             'message': b'hello again',
             'author': {
                 'name': b'Roberto Dicosmo',
                 'email': b'roberto@example.com',
                 'fullname': b'Roberto Dicosmo <roberto@example.com>',
             },
             'date': {
                 'timestamp': {
                     'seconds': 1234567843,
                     'microseconds': 220000,
                 },
                 'offset': -720,
                 'negative_utc': None,
             },
             'committer': {
                 'name': b'tony',
                 'email': b'ar@dumont.fr',
                 'fullname': b'tony <ar@dumont.fr>',
             },
             'committer_date': {
                 'timestamp': 1123456789,
                 'offset': 0,
                 'negative_utc': False,
             },
             'parents': [b'01234567890123456789'],
             'type': 'git',
             'directory': self.dir2['id'],
             'metadata': None,
             'synthetic': False
         }
 
         self.revision3 = {
             'id': hash_to_bytes('7026b7c1a2af56521e951c01ed20f255fa054238'),
             'message': b'a simple revision with no parents this time',
             'author': {
                 'name': b'Roberto Dicosmo',
                 'email': b'roberto@example.com',
                 'fullname': b'Roberto Dicosmo <roberto@example.com>',
             },
             'date': {
                 'timestamp': {
                     'seconds': 1234567843,
                     'microseconds': 220000,
                 },
                 'offset': -720,
                 'negative_utc': None,
             },
             'committer': {
                 'name': b'tony',
                 'email': b'ar@dumont.fr',
                 'fullname': b'tony <ar@dumont.fr>',
             },
             'committer_date': {
                 'timestamp': 1127351742,
                 'offset': 0,
                 'negative_utc': False,
             },
             'parents': [],
             'type': 'git',
             'directory': self.dir2['id'],
             'metadata': None,
             'synthetic': True
         }
 
         self.revision4 = {
             'id': hash_to_bytes('368a48fe15b7db2383775f97c6b247011b3f14f4'),
             'message': b'parent of self.revision2',
             'author': {
                 'name': b'me',
                 'email': b'me@soft.heri',
                 'fullname': b'me <me@soft.heri>',
             },
             'date': {
                 'timestamp': {
                     'seconds': 1244567843,
                     'microseconds': 220000,
                 },
                 'offset': -720,
                 'negative_utc': None,
             },
             'committer': {
                 'name': b'committer-dude',
                 'email': b'committer@dude.com',
                 'fullname': b'committer-dude <committer@dude.com>',
             },
             'committer_date': {
                 'timestamp': {
                     'seconds': 1244567843,
                     'microseconds': 220000,
                 },
                 'offset': -720,
                 'negative_utc': None,
             },
             'parents': [self.revision3['id']],
             'type': 'git',
             'directory': self.dir['id'],
             'metadata': None,
             'synthetic': False
         }
 
         self.origin = {
             'url': 'file:///dev/null',
             'type': 'git',
         }
 
         self.origin2 = {
             'url': 'file:///dev/zero',
             'type': 'git',
         }
 
         self.provider = {
             'name': 'hal',
             'type': 'deposit-client',
             'url': 'http:///hal/inria',
             'metadata': {
                 'location': 'France'
             }
         }
 
         self.metadata_tool = {
             'name': 'swh-deposit',
             'version': '0.0.1',
             'configuration': {
                 'sword_version': '2'
             }
         }
 
         self.origin_metadata = {
             'origin': self.origin,
             'discovery_date': datetime.datetime(2015, 1, 1, 23, 0, 0,
                                                 tzinfo=datetime.timezone.utc),
             'provider': self.provider,
             'tool': 'swh-deposit',
             'metadata': {
                 'name': 'test_origin_metadata',
                 'version': '0.0.1'
              }
         }
 
         self.origin_metadata2 = {
             'origin': self.origin,
             'discovery_date': datetime.datetime(2017, 1, 1, 23, 0, 0,
                                                 tzinfo=datetime.timezone.utc),
             'provider': self.provider,
             'tool': 'swh-deposit',
             'metadata': {
                 'name': 'test_origin_metadata',
                 'version': '0.0.1'
              }
         }
 
         self.date_visit1 = datetime.datetime(2015, 1, 1, 23, 0, 0,
                                              tzinfo=datetime.timezone.utc)
 
         self.date_visit2 = datetime.datetime(2017, 1, 1, 23, 0, 0,
                                              tzinfo=datetime.timezone.utc)
 
         self.date_visit3 = datetime.datetime(2018, 1, 1, 23, 0, 0,
                                              tzinfo=datetime.timezone.utc)
 
         self.release = {
             'id': b'87659012345678901234',
             'name': b'v0.0.1',
             'author': {
                 'name': b'olasd',
                 'email': b'nic@olasd.fr',
                 'fullname': b'olasd <nic@olasd.fr>',
             },
             'date': {
                 'timestamp': 1234567890,
                 'offset': 42,
                 'negative_utc': None,
             },
             'target': b'43210987654321098765',
             'target_type': 'revision',
             'message': b'synthetic release',
             'synthetic': True,
         }
 
         self.release2 = {
             'id': b'56789012348765901234',
             'name': b'v0.0.2',
             'author': {
                 'name': b'tony',
                 'email': b'ar@dumont.fr',
                 'fullname': b'tony <ar@dumont.fr>',
             },
             'date': {
                 'timestamp': 1634366813,
                 'offset': -120,
                 'negative_utc': None,
             },
             'target': b'432109\xa9765432\xc309\x00765',
             'target_type': 'revision',
             'message': b'v0.0.2\nMisc performance improvements + bug fixes',
             'synthetic': False
         }
 
         self.release3 = {
             'id': b'87659012345678904321',
             'name': b'v0.0.2',
             'author': {
                 'name': b'tony',
                 'email': b'tony@ardumont.fr',
                 'fullname': b'tony <tony@ardumont.fr>',
             },
             'date': {
                 'timestamp': 1634336813,
                 'offset': 0,
                 'negative_utc': False,
             },
             'target': self.revision2['id'],
             'target_type': 'revision',
             'message': b'yet another synthetic release',
             'synthetic': True,
         }
 
         self.fetch_history_date = datetime.datetime(
             2015, 1, 2, 21, 0, 0,
             tzinfo=datetime.timezone.utc)
         self.fetch_history_end = datetime.datetime(
             2015, 1, 2, 23, 0, 0,
             tzinfo=datetime.timezone.utc)
 
         self.fetch_history_duration = (self.fetch_history_end -
                                        self.fetch_history_date)
 
         self.fetch_history_data = {
             'status': True,
             'result': {'foo': 'bar'},
             'stdout': 'blabla',
             'stderr': 'blablabla',
         }
 
         self.snapshot = {
             'id': hash_to_bytes('2498dbf535f882bc7f9a18fb16c9ad27fda7bab7'),
             'branches': {
                 b'master': {
                     'target': self.revision['id'],
                     'target_type': 'revision',
                 },
             },
             'next_branch': None
         }
 
         self.empty_snapshot = {
             'id': hash_to_bytes('1a8893e6a86f444e8be8e7bda6cb34fb1735a00e'),
             'branches': {},
             'next_branch': None
         }
 
         self.complete_snapshot = {
             'id': hash_to_bytes('6e65b86363953b780d92b0a928f3e8fcdd10db36'),
             'branches': {
                 b'directory': {
                     'target': hash_to_bytes(
                         '1bd0e65f7d2ff14ae994de17a1e7fe65111dcad8'),
                     'target_type': 'directory',
                 },
                 b'content': {
                     'target': hash_to_bytes(
                         'fe95a46679d128ff167b7c55df5d02356c5a1ae1'),
                     'target_type': 'content',
                 },
                 b'alias': {
                     'target': b'revision',
                     'target_type': 'alias',
                 },
                 b'revision': {
                     'target': hash_to_bytes(
                         'aafb16d69fd30ff58afdd69036a26047f3aebdc6'),
                     'target_type': 'revision',
                 },
                 b'release': {
                     'target': hash_to_bytes(
                         '7045404f3d1c54e6473c71bbb716529fbad4be24'),
                     'target_type': 'release',
                 },
                 b'snapshot': {
                     'target': hash_to_bytes(
                         '1a8893e6a86f444e8be8e7bda6cb34fb1735a00e'),
                     'target_type': 'snapshot',
                 },
                 b'dangling': None,
             },
             'next_branch': None
         }
 
 
 class CommonTestStorage(TestStorageData):
     """Base class for Storage testing.
 
     This class is used as-is to test local storage (see TestLocalStorage
     below) and remote storage (see TestRemoteStorage in
     test_remote_storage.py.
 
     We need to have the two classes inherit from this base class
     separately to avoid nosetests running the tests from the base
     class twice.
 
     """
     maxDiff = None
 
     @staticmethod
     def normalize_entity(entity):
         entity = copy.deepcopy(entity)
         for key in ('date', 'committer_date'):
             if key in entity:
                 entity[key] = identifiers.normalize_timestamp(entity[key])
 
         return entity
 
     def test_check_config(self):
         self.assertTrue(self.storage.check_config(check_write=True))
         self.assertTrue(self.storage.check_config(check_write=False))
 
     def test_content_add(self):
         cont = self.cont
 
         actual_result = self.storage.content_add([cont])
         self.assertEqual(actual_result, {
             'content:add': 1,
-            'content:bytes:add': cont['length'],
+            'content:add:bytes': cont['length'],
             'skipped_content:add': 0
         })
 
         self.assertEqual(list(self.storage.content_get([cont['sha1']])),
                          [{'sha1': cont['sha1'], 'data': cont['data']}])
 
         expected_cont = cont.copy()
         del expected_cont['data']
         journal_objects = list(self.journal_writer.objects)
         for (obj_type, obj) in journal_objects:
             if 'ctime' in obj:
                 del obj['ctime']
         self.assertEqual(journal_objects,
                          [('content', expected_cont)])
 
     def test_content_add_same_input(self):
         cont = self.cont
 
         actual_result = self.storage.content_add([cont, cont])
         self.assertEqual(actual_result, {
             'content:add': 1,
-            'content:bytes:add': cont['length'],
+            'content:add:bytes': cont['length'],
             'skipped_content:add': 0
         })
 
     def test_content_add_different_input(self):
         cont = self.cont
         cont2 = self.cont2
 
         actual_result = self.storage.content_add([cont, cont2])
         self.assertEqual(actual_result, {
             'content:add': 2,
-            'content:bytes:add': cont['length'] + cont2['length'],
+            'content:add:bytes': cont['length'] + cont2['length'],
             'skipped_content:add': 0
         })
 
     def test_content_add_db(self):
         cont = self.cont
 
         actual_result = self.storage.content_add([cont])
 
         self.assertEqual(actual_result, {
             'content:add': 1,
-            'content:bytes:add': cont['length'],
+            'content:add:bytes': cont['length'],
             'skipped_content:add': 0
         })
 
         if hasattr(self.storage, 'objstorage'):
             self.assertIn(cont['sha1'], self.storage.objstorage)
         self.cursor.execute('SELECT sha1, sha1_git, sha256, length, status'
                             ' FROM content WHERE sha1 = %s',
                             (cont['sha1'],))
         datum = self.cursor.fetchone()
         self.assertEqual(
             (datum[0].tobytes(), datum[1].tobytes(), datum[2].tobytes(),
              datum[3], datum[4]),
             (cont['sha1'], cont['sha1_git'], cont['sha256'],
              cont['length'], 'visible'))
 
         expected_cont = cont.copy()
         del expected_cont['data']
         journal_objects = list(self.journal_writer.objects)
         for (obj_type, obj) in journal_objects:
             if 'ctime' in obj:
                 del obj['ctime']
         self.assertEqual(journal_objects,
                          [('content', expected_cont)])
 
     def test_content_add_collision(self):
         cont1 = self.cont
 
         # create (corrupted) content with same sha1{,_git} but != sha256
         cont1b = cont1.copy()
         sha256_array = bytearray(cont1b['sha256'])
         sha256_array[0] += 1
         cont1b['sha256'] = bytes(sha256_array)
 
         with self.assertRaises(HashCollision) as cm:
             self.storage.content_add([cont1, cont1b])
 
         self.assertIn(cm.exception.args[0], ['sha1', 'sha1_git', 'blake2s256'])
 
     def test_content_add_metadata(self):
         cont = self.cont.copy()
         del cont['data']
         cont['ctime'] = datetime.datetime.now()
 
         actual_result = self.storage.content_add_metadata([cont])
         self.assertEqual(actual_result, {
             'content:add': 1,
             'skipped_content:add': 0
         })
 
         expected_cont = cont.copy()
         del expected_cont['ctime']
         self.assertEqual(
             list(self.storage.content_get_metadata([cont['sha1']])),
             [expected_cont])
 
         self.assertEqual(list(self.journal_writer.objects),
                          [('content', cont)])
 
     def test_content_add_metadata_same_input(self):
         cont = self.cont.copy()
         del cont['data']
         cont['ctime'] = datetime.datetime.now()
 
         actual_result = self.storage.content_add_metadata([cont, cont])
         self.assertEqual(actual_result, {
             'content:add': 1,
             'skipped_content:add': 0
         })
 
     def test_content_add_metadata_different_input(self):
         cont = self.cont.copy()
         del cont['data']
         cont['ctime'] = datetime.datetime.now()
         cont2 = self.cont2.copy()
         del cont2['data']
         cont2['ctime'] = datetime.datetime.now()
 
         actual_result = self.storage.content_add_metadata([cont, cont2])
         self.assertEqual(actual_result, {
             'content:add': 2,
             'skipped_content:add': 0
         })
 
     def test_content_add_metadata_db(self):
         cont = self.cont.copy()
         del cont['data']
         cont['ctime'] = datetime.datetime.now()
 
         actual_result = self.storage.content_add_metadata([cont])
 
         self.assertEqual(actual_result, {
             'content:add': 1,
             'skipped_content:add': 0
         })
 
         if hasattr(self.storage, 'objstorage'):
             self.assertNotIn(cont['sha1'], self.storage.objstorage)
         self.cursor.execute('SELECT sha1, sha1_git, sha256, length, status'
                             ' FROM content WHERE sha1 = %s',
                             (cont['sha1'],))
         datum = self.cursor.fetchone()
         self.assertEqual(
             (datum[0].tobytes(), datum[1].tobytes(), datum[2].tobytes(),
              datum[3], datum[4]),
             (cont['sha1'], cont['sha1_git'], cont['sha256'],
              cont['length'], 'visible'))
 
         self.assertEqual(list(self.journal_writer.objects),
                          [('content', cont)])
 
     def test_content_add_metadata_collision(self):
         cont1 = self.cont.copy()
         del cont1['data']
         cont1['ctime'] = datetime.datetime.now()
 
         # create (corrupted) content with same sha1{,_git} but != sha256
         cont1b = cont1.copy()
         sha256_array = bytearray(cont1b['sha256'])
         sha256_array[0] += 1
         cont1b['sha256'] = bytes(sha256_array)
 
         with self.assertRaises(HashCollision) as cm:
             self.storage.content_add_metadata([cont1, cont1b])
 
         self.assertIn(cm.exception.args[0], ['sha1', 'sha1_git', 'blake2s256'])
 
     def test_skipped_content_add_db(self):
         cont = self.skipped_cont.copy()
         cont2 = self.skipped_cont2.copy()
         cont2['blake2s256'] = None
 
         actual_result = self.storage.content_add([cont, cont, cont2])
 
         self.assertEqual(actual_result, {
             'content:add': 0,
-            'content:bytes:add': 0,
+            'content:add:bytes': 0,
             'skipped_content:add': 2,
         })
 
         self.cursor.execute('SELECT sha1, sha1_git, sha256, blake2s256, '
                             'length, status, reason '
                             'FROM skipped_content ORDER BY sha1_git')
 
         datums = self.cursor.fetchall()
 
         self.assertEqual(2, len(datums))
         datum = datums[0]
         self.assertEqual(
             (datum[0].tobytes(), datum[1].tobytes(), datum[2].tobytes(),
              datum[3].tobytes(), datum[4], datum[5], datum[6]),
             (cont['sha1'], cont['sha1_git'], cont['sha256'],
              cont['blake2s256'], cont['length'], 'absent',
              'Content too long')
         )
 
         datum2 = datums[1]
         self.assertEqual(
             (datum2[0].tobytes(), datum2[1].tobytes(), datum2[2].tobytes(),
              datum2[3], datum2[4], datum2[5], datum2[6]),
             (cont2['sha1'], cont2['sha1_git'], cont2['sha256'],
              cont2['blake2s256'], cont2['length'], 'absent',
              'Content too long')
         )
 
     def test_skipped_content_add(self):
         cont = self.skipped_cont.copy()
         cont2 = self.skipped_cont2.copy()
         cont2['blake2s256'] = None
 
         missing = list(self.storage.skipped_content_missing([cont, cont2]))
 
         self.assertEqual(len(missing), 2, missing)
 
         actual_result = self.storage.content_add([cont, cont, cont2])
 
         self.assertEqual(actual_result, {
             'content:add': 0,
-            'content:bytes:add': 0,
+            'content:add:bytes': 0,
             'skipped_content:add': 2,
         })
 
         missing = list(self.storage.skipped_content_missing([cont, cont2]))
 
         self.assertEqual(missing, [])
 
     @pytest.mark.property_based
     @given(strategies.sets(
         elements=strategies.sampled_from(
             ['sha256', 'sha1_git', 'blake2s256']),
         min_size=0))
     def test_content_missing(self, algos):
         algos |= {'sha1'}
         cont2 = self.cont2
         missing_cont = self.missing_cont
         self.storage.content_add([cont2])
         test_contents = [cont2]
         missing_per_hash = defaultdict(list)
         for i in range(256):
             test_content = missing_cont.copy()
             for hash in algos:
                 test_content[hash] = bytes([i]) + test_content[hash][1:]
                 missing_per_hash[hash].append(test_content[hash])
             test_contents.append(test_content)
 
         self.assertCountEqual(
             self.storage.content_missing(test_contents),
             missing_per_hash['sha1']
         )
 
         for hash in algos:
             self.assertCountEqual(
                 self.storage.content_missing(test_contents, key_hash=hash),
                 missing_per_hash[hash]
             )
 
     def test_content_missing_per_sha1(self):
         # given
         cont2 = self.cont2
         missing_cont = self.missing_cont
         self.storage.content_add([cont2])
         # when
         gen = self.storage.content_missing_per_sha1([cont2['sha1'],
                                                      missing_cont['sha1']])
 
         # then
         self.assertEqual(list(gen), [missing_cont['sha1']])
 
     def test_content_get_metadata(self):
         cont1 = self.cont.copy()
         cont2 = self.cont2.copy()
 
         self.storage.content_add([cont1, cont2])
 
         gen = self.storage.content_get_metadata([cont1['sha1'], cont2['sha1']])
 
         # we only retrieve the metadata
         cont1.pop('data')
         cont2.pop('data')
 
         self.assertCountEqual(list(gen), [cont1, cont2])
 
     def test_content_get_metadata_missing_sha1(self):
         cont1 = self.cont.copy()
         cont2 = self.cont2.copy()
 
         missing_cont = self.missing_cont.copy()
 
         self.storage.content_add([cont1, cont2])
 
         gen = self.storage.content_get_metadata([missing_cont['sha1']])
 
         # All the metadata keys are None
         missing_cont.pop('data')
         for key in list(missing_cont):
             if key != 'sha1':
                 missing_cont[key] = None
 
         self.assertEqual(list(gen), [missing_cont])
 
     @staticmethod
     def _transform_entries(dir_, *, prefix=b''):
         for ent in dir_['entries']:
             yield {
                 'dir_id': dir_['id'],
                 'type': ent['type'],
                 'target': ent['target'],
                 'name': prefix + ent['name'],
                 'perms': ent['perms'],
                 'status': None,
                 'sha1': None,
                 'sha1_git': None,
                 'sha256': None,
                 'length': None,
             }
 
     def test_directory_add(self):
         init_missing = list(self.storage.directory_missing([self.dir['id']]))
         self.assertEqual([self.dir['id']], init_missing)
 
         actual_result = self.storage.directory_add([self.dir])
         self.assertEqual(actual_result, {'directory:add': 1})
 
         self.assertEqual(list(self.journal_writer.objects),
                          [('directory', self.dir)])
 
         actual_data = list(self.storage.directory_ls(self.dir['id']))
         expected_data = list(self._transform_entries(self.dir))
         self.assertCountEqual(expected_data, actual_data)
 
         after_missing = list(self.storage.directory_missing([self.dir['id']]))
         self.assertEqual([], after_missing)
 
     def test_directory_get_recursive(self):
         init_missing = list(self.storage.directory_missing([self.dir['id']]))
         self.assertEqual([self.dir['id']], init_missing)
 
         actual_result = self.storage.directory_add(
             [self.dir, self.dir2, self.dir3])
         self.assertEqual(actual_result, {'directory:add': 3})
 
         self.assertEqual(list(self.journal_writer.objects),
                          [('directory', self.dir),
                           ('directory', self.dir2),
                           ('directory', self.dir3)])
 
         actual_data = list(self.storage.directory_ls(
             self.dir['id'], recursive=True))
         expected_data = list(self._transform_entries(self.dir))
         self.assertCountEqual(expected_data, actual_data)
 
         actual_data = list(self.storage.directory_ls(
             self.dir2['id'], recursive=True))
         expected_data = list(self._transform_entries(self.dir2))
         self.assertCountEqual(expected_data, actual_data)
 
         actual_data = list(self.storage.directory_ls(
             self.dir3['id'], recursive=True))
         expected_data = list(itertools.chain(
             self._transform_entries(self.dir3),
             self._transform_entries(self.dir, prefix=b'subdir/')))
         self.assertCountEqual(expected_data, actual_data)
 
     def test_directory_entry_get_by_path(self):
         # given
         init_missing = list(self.storage.directory_missing([self.dir3['id']]))
         self.assertEqual([self.dir3['id']], init_missing)
 
         actual_result = self.storage.directory_add([self.dir3])
         self.assertEqual(actual_result, {'directory:add': 1})
 
         expected_entries = [
             {
                 'dir_id': self.dir3['id'],
                 'name': b'foo',
                 'type': 'file',
                 'target': self.cont['sha1_git'],
                 'sha1': None,
                 'sha1_git': None,
                 'sha256': None,
                 'status': None,
                 'perms': from_disk.DentryPerms.content,
                 'length': None,
             },
             {
                 'dir_id': self.dir3['id'],
                 'name': b'subdir',
                 'type': 'dir',
                 'target': self.dir['id'],
                 'sha1': None,
                 'sha1_git': None,
                 'sha256': None,
                 'status': None,
                 'perms': from_disk.DentryPerms.directory,
                 'length': None,
             },
             {
                 'dir_id': self.dir3['id'],
                 'name': b'hello',
                 'type': 'file',
                 'target': b'12345678901234567890',
                 'sha1': None,
                 'sha1_git': None,
                 'sha256': None,
                 'status': None,
                 'perms': from_disk.DentryPerms.content,
                 'length': None,
             },
         ]
 
         # when (all must be found here)
         for entry, expected_entry in zip(self.dir3['entries'],
                                          expected_entries):
             actual_entry = self.storage.directory_entry_get_by_path(
                 self.dir3['id'],
                 [entry['name']])
             self.assertEqual(actual_entry, expected_entry)
 
         # when (nothing should be found here since self.dir is not persisted.)
         for entry in self.dir['entries']:
             actual_entry = self.storage.directory_entry_get_by_path(
                 self.dir['id'],
                 [entry['name']])
             self.assertIsNone(actual_entry)
 
     def test_revision_add(self):
         init_missing = self.storage.revision_missing([self.revision['id']])
         self.assertEqual([self.revision['id']], list(init_missing))
 
         actual_result = self.storage.revision_add([self.revision])
         self.assertEqual(actual_result, {'revision:add': 1})
 
         end_missing = self.storage.revision_missing([self.revision['id']])
         self.assertEqual([], list(end_missing))
 
         self.assertEqual(list(self.journal_writer.objects),
                          [('revision', self.revision)])
 
         # already there so nothing added
         actual_result = self.storage.revision_add([self.revision])
         self.assertEqual(actual_result, {'revision:add': 0})
 
     def test_revision_add_name_clash(self):
         revision1 = self.revision.copy()
         revision2 = self.revision2.copy()
         revision1['author'] = {
             'fullname': b'John Doe <john.doe@example.com>',
             'name': b'John Doe',
             'email': b'john.doe@example.com'
         }
         revision2['author'] = {
             'fullname': b'John Doe <john.doe@example.com>',
             'name': b'John Doe ',
             'email': b'john.doe@example.com '
         }
         actual_result = self.storage.revision_add([revision1, revision2])
         self.assertEqual(actual_result, {'revision:add': 2})
 
     def test_revision_log(self):
         # given
         # self.revision4 -is-child-of-> self.revision3
         self.storage.revision_add([self.revision3,
                                    self.revision4])
 
         # when
         actual_results = list(self.storage.revision_log(
             [self.revision4['id']]))
 
         # hack: ids generated
         for actual_result in actual_results:
             if 'id' in actual_result['author']:
                 del actual_result['author']['id']
             if 'id' in actual_result['committer']:
                 del actual_result['committer']['id']
 
         self.assertEqual(len(actual_results), 2)  # rev4 -child-> rev3
         self.assertEqual(actual_results[0],
                          self.normalize_entity(self.revision4))
         self.assertEqual(actual_results[1],
                          self.normalize_entity(self.revision3))
 
         self.assertEqual(list(self.journal_writer.objects),
                          [('revision', self.revision3),
                           ('revision', self.revision4)])
 
     def test_revision_log_with_limit(self):
         # given
         # self.revision4 -is-child-of-> self.revision3
         self.storage.revision_add([self.revision3,
                                    self.revision4])
         actual_results = list(self.storage.revision_log(
             [self.revision4['id']], 1))
 
         # hack: ids generated
         for actual_result in actual_results:
             if 'id' in actual_result['author']:
                 del actual_result['author']['id']
             if 'id' in actual_result['committer']:
                 del actual_result['committer']['id']
 
         self.assertEqual(len(actual_results), 1)
         self.assertEqual(actual_results[0], self.revision4)
 
     def test_revision_log_unknown_revision(self):
         rev_log = list(self.storage.revision_log([self.revision['id']]))
         self.assertEqual(rev_log, [])
 
     @staticmethod
     def _short_revision(revision):
         return [revision['id'], revision['parents']]
 
     def test_revision_shortlog(self):
         # given
         # self.revision4 -is-child-of-> self.revision3
         self.storage.revision_add([self.revision3,
                                    self.revision4])
 
         # when
         actual_results = list(self.storage.revision_shortlog(
             [self.revision4['id']]))
 
         self.assertEqual(len(actual_results), 2)  # rev4 -child-> rev3
         self.assertEqual(list(actual_results[0]),
                          self._short_revision(self.revision4))
         self.assertEqual(list(actual_results[1]),
                          self._short_revision(self.revision3))
 
     def test_revision_shortlog_with_limit(self):
         # given
         # self.revision4 -is-child-of-> self.revision3
         self.storage.revision_add([self.revision3,
                                    self.revision4])
         actual_results = list(self.storage.revision_shortlog(
             [self.revision4['id']], 1))
 
         self.assertEqual(len(actual_results), 1)
         self.assertEqual(list(actual_results[0]),
                          self._short_revision(self.revision4))
 
     def test_revision_get(self):
         self.storage.revision_add([self.revision])
 
         actual_revisions = list(self.storage.revision_get(
             [self.revision['id'], self.revision2['id']]))
 
         # when
         if 'id' in actual_revisions[0]['author']:
             del actual_revisions[0]['author']['id']  # hack: ids are generated
         if 'id' in actual_revisions[0]['committer']:
             del actual_revisions[0]['committer']['id']
 
         self.assertEqual(len(actual_revisions), 2)
         self.assertEqual(actual_revisions[0],
                          self.normalize_entity(self.revision))
         self.assertIsNone(actual_revisions[1])
 
     def test_revision_get_no_parents(self):
         self.storage.revision_add([self.revision3])
 
         get = list(self.storage.revision_get([self.revision3['id']]))
 
         self.assertEqual(len(get), 1)
         self.assertEqual(get[0]['parents'], [])  # no parents on this one
 
     def test_release_add(self):
         init_missing = self.storage.release_missing([self.release['id'],
                                                      self.release2['id']])
         self.assertEqual([self.release['id'], self.release2['id']],
                          list(init_missing))
 
         actual_result = self.storage.release_add([self.release, self.release2])
         self.assertEqual(actual_result, {'release:add': 2})
 
         end_missing = self.storage.release_missing([self.release['id'],
                                                     self.release2['id']])
         self.assertEqual([], list(end_missing))
 
         self.assertEqual(list(self.journal_writer.objects),
                          [('release', self.release),
                           ('release', self.release2)])
 
         # already present so nothing added
         actual_result = self.storage.release_add([self.release, self.release2])
         self.assertEqual(actual_result, {'release:add': 0})
 
     def test_release_add_no_author_date(self):
         release = self.release.copy()
         release['author'] = None
         release['date'] = None
 
         actual_result = self.storage.release_add([release])
         self.assertEqual(actual_result, {'release:add': 1})
 
         end_missing = self.storage.release_missing([self.release['id']])
         self.assertEqual([], list(end_missing))
 
         self.assertEqual(list(self.journal_writer.objects),
                          [('release', release)])
 
     def test_release_add_name_clash(self):
         release1 = self.release.copy()
         release2 = self.release2.copy()
         release1['author'] = {
             'fullname': b'John Doe <john.doe@example.com>',
             'name': b'John Doe',
             'email': b'john.doe@example.com'
         }
         release2['author'] = {
             'fullname': b'John Doe <john.doe@example.com>',
             'name': b'John Doe ',
             'email': b'john.doe@example.com '
         }
         actual_result = self.storage.release_add([release1, release2])
         self.assertEqual(actual_result, {'release:add': 2})
 
     def test_release_get(self):
         # given
         self.storage.release_add([self.release, self.release2])
 
         # when
         actual_releases = list(self.storage.release_get([self.release['id'],
                                                          self.release2['id']]))
 
         # then
         for actual_release in actual_releases:
             if 'id' in actual_release['author']:
                 del actual_release['author']['id']  # hack: ids are generated
 
         self.assertEqual([self.normalize_entity(self.release),
                           self.normalize_entity(self.release2)],
                          [actual_releases[0], actual_releases[1]])
 
         unknown_releases = \
             list(self.storage.release_get([self.release3['id']]))
 
         self.assertIsNone(unknown_releases[0])
 
     def test_origin_add_one(self):
         origin0 = self.storage.origin_get(self.origin)
         self.assertIsNone(origin0)
 
         id = self.storage.origin_add_one(self.origin)
 
         actual_origin = self.storage.origin_get({'url': self.origin['url'],
                                                  'type': self.origin['type']})
         self.assertEqual(actual_origin['id'], id)
 
         id2 = self.storage.origin_add_one(self.origin)
 
         self.assertEqual(id, id2)
 
     def test_origin_add(self):
         origin0 = self.storage.origin_get([self.origin])[0]
         self.assertIsNone(origin0)
 
         origin1, origin2 = self.storage.origin_add([self.origin, self.origin2])
 
         actual_origin = self.storage.origin_get([{
             'url': self.origin['url'],
             'type': self.origin['type'],
         }])[0]
         self.assertEqual(actual_origin['id'], origin1['id'])
 
         actual_origin2 = self.storage.origin_get([{
             'url': self.origin2['url'],
             'type': self.origin2['type'],
         }])[0]
         self.assertEqual(actual_origin2['id'], origin2['id'])
 
         del actual_origin['id']
         del actual_origin2['id']
 
         self.assertEqual(list(self.journal_writer.objects),
                          [('origin', actual_origin),
                           ('origin', actual_origin2)])
 
     def test_origin_add_twice(self):
         add1 = self.storage.origin_add([self.origin, self.origin2])
         add2 = self.storage.origin_add([self.origin, self.origin2])
 
         self.assertEqual(add1, add2)
 
     def test_origin_get_legacy(self):
         self.assertIsNone(self.storage.origin_get(self.origin))
         id = self.storage.origin_add_one(self.origin)
 
         # lookup per type and url (returns id)
         actual_origin0 = self.storage.origin_get(
             {'url': self.origin['url'], 'type': self.origin['type']})
         self.assertEqual(actual_origin0['id'], id)
 
         # lookup per id (returns dict)
         actual_origin1 = self.storage.origin_get({'id': id})
 
         self.assertEqual(actual_origin1, {'id': id,
                                           'type': self.origin['type'],
                                           'url': self.origin['url']})
 
     def test_origin_get(self):
         self.assertIsNone(self.storage.origin_get(self.origin))
         origin_id = self.storage.origin_add_one(self.origin)
 
         # lookup per type and url (returns id)
         actual_origin0 = self.storage.origin_get(
             [{'url': self.origin['url'], 'type': self.origin['type']}])
         self.assertEqual(len(actual_origin0), 1, actual_origin0)
         self.assertEqual(actual_origin0[0]['id'], origin_id)
 
         # lookup per id (returns dict)
         actual_origin1 = self.storage.origin_get([{'id': origin_id}])
 
         self.assertEqual(len(actual_origin1), 1, actual_origin1)
         self.assertEqual(actual_origin1[0], {'id': origin_id,
                                              'type': self.origin['type'],
                                              'url': self.origin['url']})
 
     def test_origin_get_consistency(self):
         self.assertIsNone(self.storage.origin_get(self.origin))
         id = self.storage.origin_add_one(self.origin)
 
         with self.assertRaises(ValueError):
             self.storage.origin_get([
                 {'url': self.origin['url'], 'type': self.origin['type']},
                 {'id': id}])
 
     def test_origin_search(self):
         found_origins = list(self.storage.origin_search(self.origin['url']))
         self.assertEqual(len(found_origins), 0)
 
         found_origins = list(self.storage.origin_search(self.origin['url'],
                                                         regexp=True))
         self.assertEqual(len(found_origins), 0)
 
         id = self.storage.origin_add_one(self.origin)
         origin_data = {'id': id,
                        'type': self.origin['type'],
                        'url': self.origin['url']}
         found_origins = list(self.storage.origin_search(self.origin['url']))
         self.assertEqual(len(found_origins), 1)
         self.assertEqual(found_origins[0], origin_data)
 
         found_origins = list(self.storage.origin_search(
             '.' + self.origin['url'][1:-1] + '.', regexp=True))
         self.assertEqual(len(found_origins), 1)
         self.assertEqual(found_origins[0], origin_data)
 
         id2 = self.storage.origin_add_one(self.origin2)
         origin2_data = {'id': id2,
                         'type': self.origin2['type'],
                         'url': self.origin2['url']}
         found_origins = list(self.storage.origin_search(self.origin2['url']))
         self.assertEqual(len(found_origins), 1)
         self.assertEqual(found_origins[0], origin2_data)
 
         found_origins = list(self.storage.origin_search(
             '.' + self.origin2['url'][1:-1] + '.', regexp=True))
         self.assertEqual(len(found_origins), 1)
         self.assertEqual(found_origins[0], origin2_data)
 
         found_origins = list(self.storage.origin_search('/'))
         self.assertEqual(len(found_origins), 2)
 
         found_origins = list(self.storage.origin_search('.*/.*', regexp=True))
         self.assertEqual(len(found_origins), 2)
 
         found_origins = list(self.storage.origin_search('/', offset=0, limit=1)) # noqa
         self.assertEqual(len(found_origins), 1)
         self.assertEqual(found_origins[0], origin_data)
 
         found_origins = list(self.storage.origin_search('.*/.*', offset=0, limit=1, regexp=True)) # noqa
         self.assertEqual(len(found_origins), 1)
         self.assertEqual(found_origins[0], origin_data)
 
         found_origins = list(self.storage.origin_search('/', offset=1, limit=1)) # noqa
         self.assertEqual(len(found_origins), 1)
         self.assertEqual(found_origins[0], origin2_data)
 
         found_origins = list(self.storage.origin_search('.*/.*', offset=1, limit=1, regexp=True)) # noqa
         self.assertEqual(len(found_origins), 1)
         self.assertEqual(found_origins[0], origin2_data)
 
     def test_origin_visit_add(self):
         # given
         self.assertIsNone(self.storage.origin_get([self.origin2])[0])
 
         origin_id = self.storage.origin_add_one(self.origin2)
         self.assertIsNotNone(origin_id)
 
         # when
         origin_visit1 = self.storage.origin_visit_add(
             origin_id,
             date=self.date_visit2)
 
         # then
         self.assertEqual(origin_visit1['origin'], origin_id)
         self.assertIsNotNone(origin_visit1['visit'])
 
         actual_origin_visits = list(self.storage.origin_visit_get(origin_id))
         self.assertEqual(actual_origin_visits,
                          [{
                              'origin': origin_id,
                              'date': self.date_visit2,
                              'visit': origin_visit1['visit'],
                              'status': 'ongoing',
                              'metadata': None,
                              'snapshot': None,
                          }])
 
         expected_origin = self.origin2.copy()
         data = {
             'origin': expected_origin,
             'date': self.date_visit2,
             'visit': origin_visit1['visit'],
             'status': 'ongoing',
             'metadata': None,
             'snapshot': None,
         }
         self.assertEqual(list(self.journal_writer.objects),
                          [('origin', expected_origin),
                           ('origin_visit', data)])
 
     def test_origin_visit_update(self):
         # given
         origin_id = self.storage.origin_add_one(self.origin2)
         origin_id2 = self.storage.origin_add_one(self.origin)
 
         origin_visit1 = self.storage.origin_visit_add(
             origin_id,
             date=self.date_visit2)
 
         origin_visit2 = self.storage.origin_visit_add(
             origin_id,
             date=self.date_visit3)
 
         origin_visit3 = self.storage.origin_visit_add(
             origin_id2,
             date=self.date_visit3)
 
         # when
         visit1_metadata = {
             'contents': 42,
             'directories': 22,
         }
         self.storage.origin_visit_update(
             origin_id, origin_visit1['visit'], status='full',
             metadata=visit1_metadata)
         self.storage.origin_visit_update(origin_id2, origin_visit3['visit'],
                                          status='partial')
 
         # then
         actual_origin_visits = list(self.storage.origin_visit_get(origin_id))
         self.assertEqual(actual_origin_visits, [{
             'origin': origin_visit2['origin'],
             'date': self.date_visit2,
             'visit': origin_visit1['visit'],
             'status': 'full',
             'metadata': visit1_metadata,
             'snapshot': None,
         }, {
             'origin': origin_visit2['origin'],
             'date': self.date_visit3,
             'visit': origin_visit2['visit'],
             'status': 'ongoing',
             'metadata': None,
             'snapshot': None,
         }])
 
         actual_origin_visits_bis = list(self.storage.origin_visit_get(
             origin_id, limit=1))
         self.assertEqual(actual_origin_visits_bis,
                          [{
                              'origin': origin_visit2['origin'],
                              'date': self.date_visit2,
                              'visit': origin_visit1['visit'],
                              'status': 'full',
                              'metadata': visit1_metadata,
                              'snapshot': None,
                          }])
 
         actual_origin_visits_ter = list(self.storage.origin_visit_get(
             origin_id, last_visit=origin_visit1['visit']))
         self.assertEqual(actual_origin_visits_ter,
                          [{
                              'origin': origin_visit2['origin'],
                              'date': self.date_visit3,
                              'visit': origin_visit2['visit'],
                              'status': 'ongoing',
                              'metadata': None,
                              'snapshot': None,
                          }])
 
         actual_origin_visits2 = list(self.storage.origin_visit_get(origin_id2))
         self.assertEqual(actual_origin_visits2,
                          [{
                              'origin': origin_visit3['origin'],
                              'date': self.date_visit3,
                              'visit': origin_visit3['visit'],
                              'status': 'partial',
                              'metadata': None,
                              'snapshot': None,
                          }])
 
         expected_origin = self.origin2.copy()
         expected_origin2 = self.origin.copy()
         data1 = {
             'origin': expected_origin,
             'date': self.date_visit2,
             'visit': origin_visit1['visit'],
             'status': 'ongoing',
             'metadata': None,
             'snapshot': None,
         }
         data2 = {
             'origin': expected_origin,
             'date': self.date_visit3,
             'visit': origin_visit2['visit'],
             'status': 'ongoing',
             'metadata': None,
             'snapshot': None,
         }
         data3 = {
             'origin': expected_origin2,
             'date': self.date_visit3,
             'visit': origin_visit3['visit'],
             'status': 'ongoing',
             'metadata': None,
             'snapshot': None,
         }
         data4 = {
             'origin': expected_origin,
             'date': self.date_visit2,
             'visit': origin_visit1['visit'],
             'metadata': visit1_metadata,
             'status': 'full',
             'snapshot': None,
         }
         data5 = {
             'origin': expected_origin2,
             'date': self.date_visit3,
             'visit': origin_visit3['visit'],
             'status': 'partial',
             'metadata': None,
             'snapshot': None,
         }
         self.assertEqual(list(self.journal_writer.objects),
                          [('origin', expected_origin),
                           ('origin', expected_origin2),
                           ('origin_visit', data1),
                           ('origin_visit', data2),
                           ('origin_visit', data3),
                           ('origin_visit', data4),
                           ('origin_visit', data5)])
 
     def test_origin_visit_update_missing_snapshot(self):
         # given
         origin_id = self.storage.origin_add_one(self.origin)
 
         origin_visit = self.storage.origin_visit_add(
             origin_id,
             date=self.date_visit1)
 
         # when
         self.storage.origin_visit_update(
             origin_id, origin_visit['visit'],
             snapshot=self.snapshot['id'])
 
         # then
         actual_origin_visit = self.storage.origin_visit_get_by(
             origin_visit['origin'], origin_visit['visit'])
         self.assertEqual(actual_origin_visit['snapshot'], self.snapshot['id'])
 
         # when
         self.storage.snapshot_add([self.snapshot])
         self.assertEqual(actual_origin_visit['snapshot'], self.snapshot['id'])
 
     def test_origin_visit_get_by(self):
         origin_id = self.storage.origin_add_one(self.origin2)
         origin_id2 = self.storage.origin_add_one(self.origin)
 
         origin_visit1 = self.storage.origin_visit_add(
             origin_id,
             date=self.date_visit2)
 
         self.storage.snapshot_add(origin_id, origin_visit1['visit'],
                                   self.snapshot)
 
         # Add some other {origin, visit} entries
         self.storage.origin_visit_add(origin_id, date=self.date_visit3)
         self.storage.origin_visit_add(origin_id2, date=self.date_visit3)
 
         # when
         visit1_metadata = {
             'contents': 42,
             'directories': 22,
         }
 
         self.storage.origin_visit_update(
             origin_id, origin_visit1['visit'], status='full',
             metadata=visit1_metadata)
 
         expected_origin_visit = origin_visit1.copy()
         expected_origin_visit.update({
             'origin': origin_id,
             'visit': origin_visit1['visit'],
             'date': self.date_visit2,
             'metadata': visit1_metadata,
             'status': 'full',
             'snapshot': self.snapshot['id'],
         })
 
         # when
         actual_origin_visit1 = self.storage.origin_visit_get_by(
             origin_visit1['origin'], origin_visit1['visit'])
 
         # then
         self.assertEqual(actual_origin_visit1, expected_origin_visit)
 
     def test_origin_visit_upsert_new(self):
         # given
         self.assertIsNone(self.storage.origin_get([self.origin2])[0])
 
         origin_id = self.storage.origin_add_one(self.origin2)
         self.assertIsNotNone(origin_id)
 
         # when
         self.storage.origin_visit_upsert([{
              'origin': origin_id,
              'date': self.date_visit2,
              'visit': 123,
              'status': 'full',
              'metadata': None,
              'snapshot': None,
          }])
 
         # then
         actual_origin_visits = list(self.storage.origin_visit_get(origin_id))
         self.assertEqual(actual_origin_visits,
                          [{
                              'origin': origin_id,
                              'date': self.date_visit2,
                              'visit': 123,
                              'status': 'full',
                              'metadata': None,
                              'snapshot': None,
                          }])
 
         expected_origin = self.origin2.copy()
         data = {
             'origin': expected_origin,
             'date': self.date_visit2,
             'visit': 123,
             'status': 'full',
             'metadata': None,
             'snapshot': None,
         }
         self.assertEqual(list(self.journal_writer.objects),
                          [('origin', expected_origin),
                           ('origin_visit', data)])
 
     def test_origin_visit_upsert_existing(self):
         # given
         self.assertIsNone(self.storage.origin_get([self.origin2])[0])
 
         origin_id = self.storage.origin_add_one(self.origin2)
         self.assertIsNotNone(origin_id)
 
         # when
         origin_visit1 = self.storage.origin_visit_add(
             origin_id,
             date=self.date_visit2)
         self.storage.origin_visit_upsert([{
              'origin': origin_id,
              'date': self.date_visit2,
              'visit': origin_visit1['visit'],
              'status': 'full',
              'metadata': None,
              'snapshot': None,
          }])
 
         # then
         self.assertEqual(origin_visit1['origin'], origin_id)
         self.assertIsNotNone(origin_visit1['visit'])
 
         actual_origin_visits = list(self.storage.origin_visit_get(origin_id))
         self.assertEqual(actual_origin_visits,
                          [{
                              'origin': origin_id,
                              'date': self.date_visit2,
                              'visit': origin_visit1['visit'],
                              'status': 'full',
                              'metadata': None,
                              'snapshot': None,
                          }])
 
         expected_origin = self.origin2.copy()
         data1 = {
             'origin': expected_origin,
             'date': self.date_visit2,
             'visit': origin_visit1['visit'],
             'status': 'ongoing',
             'metadata': None,
             'snapshot': None,
         }
         data2 = {
             'origin': expected_origin,
             'date': self.date_visit2,
             'visit': origin_visit1['visit'],
             'status': 'full',
             'metadata': None,
             'snapshot': None,
         }
         self.assertEqual(list(self.journal_writer.objects),
                          [('origin', expected_origin),
                           ('origin_visit', data1),
                           ('origin_visit', data2)])
 
     def test_origin_visit_get_by_no_result(self):
         # No result
         actual_origin_visit = self.storage.origin_visit_get_by(
             10, 999)
 
         self.assertIsNone(actual_origin_visit)
 
     def test_person_get(self):
         # given (person injection through revision for example)
         self.storage.revision_add([self.revision])
         rev = list(self.storage.revision_get([self.revision['id']]))[0]
 
         id0 = rev['committer']['id']
         person0 = self.revision['committer']
 
         id1 = rev['author']['id']
         person1 = self.revision['author']
 
         # when
         actual_persons = self.storage.person_get([id0, id1])
 
         # then
         expected_persons = [
             {
                 'id': id0,
                 'fullname': person0['fullname'],
                 'name': person0['name'],
                 'email': person0['email'],
             },
             {
                 'id': id1,
                 'fullname': person1['fullname'],
                 'name': person1['name'],
                 'email': person1['email'],
             }
         ]
         self.assertEqual(list(actual_persons), expected_persons)
 
         # when
         actual_persons = self.storage.person_get([id1, id0])
 
         # then
         expected_persons.reverse()
         self.assertEqual(list(actual_persons), expected_persons)
 
     def test_person_get_fullname_unicity(self):
         # given (person injection through revisions for example)
         revision = self.revision
 
         # create a revision with same committer fullname but wo name and email
         revision2 = copy.deepcopy(self.revision2)
         revision2['committer'] = dict(revision['committer'])
         revision2['committer']['email'] = None
         revision2['committer']['name'] = None
 
         self.storage.revision_add([revision])
         self.storage.revision_add([revision2])
 
         # when getting added revisions
         revisions = list(
             self.storage.revision_get([revision['id'], revision2['id']]))
 
         # then
         # check committers are the same
         self.assertEqual(revisions[0]['committer'],
                          revisions[1]['committer'])
 
         # check person_get return same result
         person0 = list(
             self.storage.person_get([revisions[0]['committer']['id']]))[0]
 
         person1 = list(
             self.storage.person_get([revisions[1]['committer']['id']]))[0]
 
         self.assertEqual(person0, person1)
 
     def test_snapshot_add_get_empty(self):
         origin_id = self.storage.origin_add_one(self.origin)
         origin_visit1 = self.storage.origin_visit_add(origin_id,
                                                       self.date_visit1)
         visit_id = origin_visit1['visit']
 
         actual_result = self.storage.snapshot_add([self.empty_snapshot])
         self.assertEqual(actual_result, {'snapshot:add': 1})
 
         self.storage.origin_visit_update(
             origin_id, visit_id, snapshot=self.empty_snapshot['id'])
 
         by_id = self.storage.snapshot_get(self.empty_snapshot['id'])
         self.assertEqual(by_id, self.empty_snapshot)
 
         by_ov = self.storage.snapshot_get_by_origin_visit(origin_id, visit_id)
         self.assertEqual(by_ov, self.empty_snapshot)
 
         expected_origin = self.origin.copy()
         data1 = {
             'origin': expected_origin,
             'date': self.date_visit1,
             'visit': origin_visit1['visit'],
             'status': 'ongoing',
             'metadata': None,
             'snapshot': None,
         }
         data2 = {
             'origin': expected_origin,
             'date': self.date_visit1,
             'visit': origin_visit1['visit'],
             'status': 'ongoing',
             'metadata': None,
             'snapshot': self.empty_snapshot['id'],
         }
         self.assertEqual(list(self.journal_writer.objects),
                          [('origin', expected_origin),
                           ('origin_visit', data1),
                           ('snapshot', self.empty_snapshot),
                           ('origin_visit', data2)])
 
     def test_snapshot_add_get_empty__legacy_add(self):
         origin_id = self.storage.origin_add_one(self.origin)
         origin_visit1 = self.storage.origin_visit_add(origin_id,
                                                       self.date_visit1)
         visit_id = origin_visit1['visit']
 
         self.storage.snapshot_add(origin_id, visit_id, self.empty_snapshot)
 
         by_id = self.storage.snapshot_get(self.empty_snapshot['id'])
         self.assertEqual(by_id, self.empty_snapshot)
 
         by_ov = self.storage.snapshot_get_by_origin_visit(origin_id, visit_id)
         self.assertEqual(by_ov, self.empty_snapshot)
 
         expected_origin = self.origin.copy()
         data1 = {
             'origin': expected_origin,
             'date': self.date_visit1,
             'visit': origin_visit1['visit'],
             'status': 'ongoing',
             'metadata': None,
             'snapshot': None,
         }
         data2 = {
             'origin': expected_origin,
             'date': self.date_visit1,
             'visit': origin_visit1['visit'],
             'status': 'ongoing',
             'metadata': None,
             'snapshot': self.empty_snapshot['id'],
         }
         self.assertEqual(list(self.journal_writer.objects),
                          [('origin', expected_origin),
                           ('origin_visit', data1),
                           ('snapshot', self.empty_snapshot),
                           ('origin_visit', data2)])
 
     def test_snapshot_add_get_complete(self):
         origin_id = self.storage.origin_add_one(self.origin)
         origin_visit1 = self.storage.origin_visit_add(origin_id,
                                                       self.date_visit1)
         visit_id = origin_visit1['visit']
 
         actual_result = self.storage.snapshot_add(
             origin_id, visit_id, self.complete_snapshot)
         self.assertEqual(actual_result, {'snapshot:add': 1})
 
         by_id = self.storage.snapshot_get(self.complete_snapshot['id'])
         self.assertEqual(by_id, self.complete_snapshot)
 
         by_ov = self.storage.snapshot_get_by_origin_visit(origin_id, visit_id)
         self.assertEqual(by_ov, self.complete_snapshot)
 
     def test_snapshot_add_many(self):
         actual_result = self.storage.snapshot_add(
             [self.snapshot, self.complete_snapshot])
         self.assertEqual(actual_result, {'snapshot:add': 2})
 
         self.assertEqual(
             self.complete_snapshot,
             self.storage.snapshot_get(self.complete_snapshot['id']))
 
         self.assertEqual(
             self.snapshot,
             self.storage.snapshot_get(self.snapshot['id']))
 
     def test_snapshot_add_many_incremental(self):
         actual_result = self.storage.snapshot_add([self.complete_snapshot])
         self.assertEqual(actual_result, {'snapshot:add': 1})
 
         actual_result2 = self.storage.snapshot_add(
             [self.snapshot, self.complete_snapshot])
         self.assertEqual(actual_result2, {'snapshot:add': 1})
 
         self.assertEqual(
             self.complete_snapshot,
             self.storage.snapshot_get(self.complete_snapshot['id']))
 
         self.assertEqual(
             self.snapshot,
             self.storage.snapshot_get(self.snapshot['id']))
 
     def test_snapshot_add_count_branches(self):
         origin_id = self.storage.origin_add_one(self.origin)
         origin_visit1 = self.storage.origin_visit_add(origin_id,
                                                       self.date_visit1)
         visit_id = origin_visit1['visit']
 
         actual_result = self.storage.snapshot_add(
             origin_id, visit_id, self.complete_snapshot)
         self.assertEqual(actual_result, {'snapshot:add': 1})
 
         snp_id = self.complete_snapshot['id']
         snp_size = self.storage.snapshot_count_branches(snp_id)
 
         expected_snp_size = {
             'alias': 1,
             'content': 1,
             'directory': 1,
             'release': 1,
             'revision': 1,
             'snapshot': 1,
             None: 1
         }
 
         self.assertEqual(snp_size, expected_snp_size)
 
     def test_snapshot_add_get_paginated(self):
         origin_id = self.storage.origin_add_one(self.origin)
         origin_visit1 = self.storage.origin_visit_add(origin_id,
                                                       self.date_visit1)
         visit_id = origin_visit1['visit']
 
         self.storage.snapshot_add(origin_id, visit_id, self.complete_snapshot)
 
         snp_id = self.complete_snapshot['id']
         branches = self.complete_snapshot['branches']
         branch_names = list(sorted(branches))
 
         snapshot = self.storage.snapshot_get_branches(snp_id,
                                                       branches_from=b'release')
 
         rel_idx = branch_names.index(b'release')
         expected_snapshot = {
             'id': snp_id,
             'branches': {
                 name: branches[name]
                 for name in branch_names[rel_idx:]
             },
             'next_branch': None,
         }
 
         self.assertEqual(snapshot, expected_snapshot)
 
         snapshot = self.storage.snapshot_get_branches(snp_id,
                                                       branches_count=1)
 
         expected_snapshot = {
             'id': snp_id,
             'branches': {
                  branch_names[0]: branches[branch_names[0]],
             },
             'next_branch': b'content',
         }
         self.assertEqual(snapshot, expected_snapshot)
 
         snapshot = self.storage.snapshot_get_branches(
             snp_id, branches_from=b'directory', branches_count=3)
 
         dir_idx = branch_names.index(b'directory')
         expected_snapshot = {
             'id': snp_id,
             'branches': {
                 name: branches[name]
                 for name in branch_names[dir_idx:dir_idx + 3]
             },
             'next_branch': branch_names[dir_idx + 3],
         }
 
         self.assertEqual(snapshot, expected_snapshot)
 
     def test_snapshot_add_get_filtered(self):
         origin_id = self.storage.origin_add_one(self.origin)
         origin_visit1 = self.storage.origin_visit_add(origin_id,
                                                       self.date_visit1)
         visit_id = origin_visit1['visit']
 
         self.storage.snapshot_add(origin_id, visit_id, self.complete_snapshot)
 
         snp_id = self.complete_snapshot['id']
         branches = self.complete_snapshot['branches']
 
         snapshot = self.storage.snapshot_get_branches(
             snp_id, target_types=['release', 'revision'])
 
         expected_snapshot = {
             'id': snp_id,
             'branches': {
                 name: tgt
                 for name, tgt in branches.items()
                 if tgt and tgt['target_type'] in ['release', 'revision']
             },
             'next_branch': None,
         }
 
         self.assertEqual(snapshot, expected_snapshot)
 
         snapshot = self.storage.snapshot_get_branches(snp_id,
                                                       target_types=['alias'])
 
         expected_snapshot = {
             'id': snp_id,
             'branches': {
                 name: tgt
                 for name, tgt in branches.items()
                 if tgt and tgt['target_type'] == 'alias'
             },
             'next_branch': None,
         }
 
         self.assertEqual(snapshot, expected_snapshot)
 
     def test_snapshot_add_get(self):
         origin_id = self.storage.origin_add_one(self.origin)
         origin_visit1 = self.storage.origin_visit_add(origin_id,
                                                       self.date_visit1)
         visit_id = origin_visit1['visit']
 
         self.storage.snapshot_add(origin_id, visit_id, self.snapshot)
 
         by_id = self.storage.snapshot_get(self.snapshot['id'])
         self.assertEqual(by_id, self.snapshot)
 
         by_ov = self.storage.snapshot_get_by_origin_visit(origin_id, visit_id)
         self.assertEqual(by_ov, self.snapshot)
 
         origin_visit_info = self.storage.origin_visit_get_by(origin_id,
                                                              visit_id)
         self.assertEqual(origin_visit_info['snapshot'], self.snapshot['id'])
 
     def test_snapshot_add_nonexistent_visit(self):
         origin_id = self.storage.origin_add_one(self.origin)
         visit_id = 54164461156
 
         self.journal_writer.objects[:] = []
 
         self.storage.snapshot_add([self.snapshot])
 
         with self.assertRaises(ValueError):
             self.storage.origin_visit_update(
                 origin_id, visit_id, snapshot=self.snapshot['id'])
 
         self.assertEqual(list(self.journal_writer.objects), [
             ('snapshot', self.snapshot)])
 
     def test_snapshot_add_nonexistent_visit__legacy_add(self):
         origin_id = self.storage.origin_add_one(self.origin)
         visit_id = 54164461156
 
         self.journal_writer.objects[:] = []
 
         with self.assertRaises(ValueError):
             self.storage.snapshot_add(origin_id, visit_id, self.snapshot)
 
         # Note: the actual legacy behavior was to abort before adding
         # the snapshot; but delaying non-existence checks makes the
         # compatibility code simpler
         self.assertEqual(list(self.journal_writer.objects), [
             ('snapshot', self.snapshot)])
 
     def test_snapshot_add_twice(self):
         origin_id = self.storage.origin_add_one(self.origin)
         origin_visit1 = self.storage.origin_visit_add(origin_id,
                                                       self.date_visit1)
         visit1_id = origin_visit1['visit']
         self.storage.snapshot_add([self.snapshot])
         self.storage.origin_visit_update(
             origin_id, visit1_id, snapshot=self.snapshot['id'])
 
         by_ov1 = self.storage.snapshot_get_by_origin_visit(origin_id,
                                                            visit1_id)
         self.assertEqual(by_ov1, self.snapshot)
 
         origin_visit2 = self.storage.origin_visit_add(origin_id,
                                                       self.date_visit2)
         visit2_id = origin_visit2['visit']
 
         self.storage.snapshot_add([self.snapshot])
         self.storage.origin_visit_update(
             origin_id, visit2_id, snapshot=self.snapshot['id'])
 
         by_ov2 = self.storage.snapshot_get_by_origin_visit(origin_id,
                                                            visit2_id)
         self.assertEqual(by_ov2, self.snapshot)
 
         expected_origin = self.origin.copy()
         data1 = {
             'origin': expected_origin,
             'date': self.date_visit1,
             'visit': origin_visit1['visit'],
             'status': 'ongoing',
             'metadata': None,
             'snapshot': None,
         }
         data2 = {
             'origin': expected_origin,
             'date': self.date_visit1,
             'visit': origin_visit1['visit'],
             'status': 'ongoing',
             'metadata': None,
             'snapshot': self.snapshot['id'],
         }
         data3 = {
             'origin': expected_origin,
             'date': self.date_visit2,
             'visit': origin_visit2['visit'],
             'status': 'ongoing',
             'metadata': None,
             'snapshot': None,
         }
         data4 = {
             'origin': expected_origin,
             'date': self.date_visit2,
             'visit': origin_visit2['visit'],
             'status': 'ongoing',
             'metadata': None,
             'snapshot': self.snapshot['id'],
         }
         self.assertEqual(list(self.journal_writer.objects),
                          [('origin', expected_origin),
                           ('origin_visit', data1),
                           ('snapshot', self.snapshot),
                           ('origin_visit', data2),
                           ('origin_visit', data3),
                           ('origin_visit', data4)])
 
     def test_snapshot_add_twice__legacy_add(self):
         origin_id = self.storage.origin_add_one(self.origin)
         origin_visit1 = self.storage.origin_visit_add(origin_id,
                                                       self.date_visit1)
         visit1_id = origin_visit1['visit']
         self.storage.snapshot_add(origin_id, visit1_id, self.snapshot)
 
         by_ov1 = self.storage.snapshot_get_by_origin_visit(origin_id,
                                                            visit1_id)
         self.assertEqual(by_ov1, self.snapshot)
 
         origin_visit2 = self.storage.origin_visit_add(origin_id,
                                                       self.date_visit2)
         visit2_id = origin_visit2['visit']
 
         self.storage.snapshot_add(origin_id, visit2_id, self.snapshot)
 
         by_ov2 = self.storage.snapshot_get_by_origin_visit(origin_id,
                                                            visit2_id)
         self.assertEqual(by_ov2, self.snapshot)
 
         expected_origin = self.origin.copy()
         data1 = {
             'origin': expected_origin,
             'date': self.date_visit1,
             'visit': origin_visit1['visit'],
             'status': 'ongoing',
             'metadata': None,
             'snapshot': None,
         }
         data2 = {
             'origin': expected_origin,
             'date': self.date_visit1,
             'visit': origin_visit1['visit'],
             'status': 'ongoing',
             'metadata': None,
             'snapshot': self.snapshot['id'],
         }
         data3 = {
             'origin': expected_origin,
             'date': self.date_visit2,
             'visit': origin_visit2['visit'],
             'status': 'ongoing',
             'metadata': None,
             'snapshot': None,
         }
         data4 = {
             'origin': expected_origin,
             'date': self.date_visit2,
             'visit': origin_visit2['visit'],
             'status': 'ongoing',
             'metadata': None,
             'snapshot': self.snapshot['id'],
         }
         self.assertEqual(list(self.journal_writer.objects),
                          [('origin', expected_origin),
                           ('origin_visit', data1),
                           ('snapshot', self.snapshot),
                           ('origin_visit', data2),
                           ('origin_visit', data3),
                           ('origin_visit', data4)])
 
     def test_snapshot_get_nonexistent(self):
         bogus_snapshot_id = b'bogus snapshot id 00'
         bogus_origin_id = 1
         bogus_visit_id = 1
 
         by_id = self.storage.snapshot_get(bogus_snapshot_id)
         self.assertIsNone(by_id)
 
         by_ov = self.storage.snapshot_get_by_origin_visit(bogus_origin_id,
                                                           bogus_visit_id)
         self.assertIsNone(by_ov)
 
     def test_snapshot_get_latest(self):
         origin_id = self.storage.origin_add_one(self.origin)
         origin_visit1 = self.storage.origin_visit_add(origin_id,
                                                       self.date_visit1)
         visit1_id = origin_visit1['visit']
         origin_visit2 = self.storage.origin_visit_add(origin_id,
                                                       self.date_visit2)
         visit2_id = origin_visit2['visit']
 
         # Add a visit with the same date as the previous one
         origin_visit3 = self.storage.origin_visit_add(origin_id,
                                                       self.date_visit2)
         visit3_id = origin_visit3['visit']
 
         # Two visits, both with no snapshot: latest snapshot is None
         self.assertIsNone(self.storage.snapshot_get_latest(origin_id))
 
         # Add snapshot to visit1, latest snapshot = visit 1 snapshot
         self.storage.snapshot_add([self.complete_snapshot])
         self.storage.origin_visit_update(
             origin_id, visit1_id, snapshot=self.complete_snapshot['id'])
         self.assertEqual(self.complete_snapshot,
                          self.storage.snapshot_get_latest(origin_id))
 
         # Status filter: both visits are status=ongoing, so no snapshot
         # returned
         self.assertIsNone(
             self.storage.snapshot_get_latest(origin_id,
                                              allowed_statuses=['full'])
         )
 
         # Mark the first visit as completed and check status filter again
         self.storage.origin_visit_update(origin_id, visit1_id, status='full')
         self.assertEqual(
             self.complete_snapshot,
             self.storage.snapshot_get_latest(origin_id,
                                              allowed_statuses=['full']),
         )
 
         # Add snapshot to visit2 and check that the new snapshot is returned
         self.storage.snapshot_add([self.empty_snapshot])
         self.storage.origin_visit_update(
             origin_id, visit2_id, snapshot=self.empty_snapshot['id'])
         self.assertEqual(self.empty_snapshot,
                          self.storage.snapshot_get_latest(origin_id))
 
         # Check that the status filter is still working
         self.assertEqual(
             self.complete_snapshot,
             self.storage.snapshot_get_latest(origin_id,
                                              allowed_statuses=['full']),
         )
 
         # Add snapshot to visit3 (same date as visit2) and check that
         # the new snapshot is returned
         self.storage.snapshot_add([self.complete_snapshot])
         self.storage.origin_visit_update(
             origin_id, visit3_id, snapshot=self.complete_snapshot['id'])
         self.assertEqual(self.complete_snapshot,
                          self.storage.snapshot_get_latest(origin_id))
 
     def test_snapshot_get_latest__missing_snapshot(self):
         origin_id = self.storage.origin_add_one(self.origin)
         origin_visit1 = self.storage.origin_visit_add(origin_id,
                                                       self.date_visit1)
         visit1_id = origin_visit1['visit']
         origin_visit2 = self.storage.origin_visit_add(origin_id,
                                                       self.date_visit2)
         visit2_id = origin_visit2['visit']
 
         # Two visits, both with no snapshot: latest snapshot is None
         self.assertIsNone(self.storage.snapshot_get_latest(origin_id))
 
         # Add unknown snapshot to visit1, latest snapshot = None
         self.storage.origin_visit_update(
             origin_id, visit1_id, snapshot=self.complete_snapshot['id'])
         self.assertIsNone(self.storage.snapshot_get_latest(origin_id))
 
         # Status filter: both visits are status=ongoing, so no snapshot
         # returned
         self.assertIsNone(
             self.storage.snapshot_get_latest(origin_id,
                                              allowed_statuses=['full'])
         )
 
         # Mark the first visit as completed and check status filter again
         self.storage.origin_visit_update(origin_id, visit1_id, status='full')
         self.assertIsNone(
             self.storage.snapshot_get_latest(origin_id,
                                              allowed_statuses=['full']),
         )
 
         # Actually add the snapshot and check status filter again
         self.storage.snapshot_add([self.complete_snapshot])
         self.assertEqual(
             self.complete_snapshot,
             self.storage.snapshot_get_latest(origin_id)
         )
 
         # Add unknown snapshot to visit2 and check that the old snapshot
         # is still returned
         self.storage.origin_visit_update(
             origin_id, visit2_id, snapshot=self.empty_snapshot['id'])
         self.assertEqual(
             self.complete_snapshot,
             self.storage.snapshot_get_latest(origin_id))
 
         # Actually add that snapshot and check that the new one is returned
         self.storage.snapshot_add([self.empty_snapshot])
         self.assertEqual(
             self.empty_snapshot,
             self.storage.snapshot_get_latest(origin_id)
         )
 
     def test_snapshot_get_latest__legacy_add(self):
         origin_id = self.storage.origin_add_one(self.origin)
         origin_visit1 = self.storage.origin_visit_add(origin_id,
                                                       self.date_visit1)
         visit1_id = origin_visit1['visit']
         origin_visit2 = self.storage.origin_visit_add(origin_id,
                                                       self.date_visit2)
         visit2_id = origin_visit2['visit']
 
         # Add a visit with the same date as the previous one
         origin_visit3 = self.storage.origin_visit_add(origin_id,
                                                       self.date_visit2)
         visit3_id = origin_visit3['visit']
 
         # Two visits, both with no snapshot: latest snapshot is None
         self.assertIsNone(self.storage.snapshot_get_latest(origin_id))
 
         # Add snapshot to visit1, latest snapshot = visit 1 snapshot
         self.storage.snapshot_add(origin_id, visit1_id, self.complete_snapshot)
         self.assertEqual(self.complete_snapshot,
                          self.storage.snapshot_get_latest(origin_id))
 
         # Status filter: both visits are status=ongoing, so no snapshot
         # returned
         self.assertIsNone(
             self.storage.snapshot_get_latest(origin_id,
                                              allowed_statuses=['full'])
         )
 
         # Mark the first visit as completed and check status filter again
         self.storage.origin_visit_update(origin_id, visit1_id, status='full')
         self.assertEqual(
             self.complete_snapshot,
             self.storage.snapshot_get_latest(origin_id,
                                              allowed_statuses=['full']),
         )
 
         # Add snapshot to visit2 and check that the new snapshot is returned
         self.storage.snapshot_add(origin_id, visit2_id, self.empty_snapshot)
         self.assertEqual(self.empty_snapshot,
                          self.storage.snapshot_get_latest(origin_id))
 
         # Check that the status filter is still working
         self.assertEqual(
             self.complete_snapshot,
             self.storage.snapshot_get_latest(origin_id,
                                              allowed_statuses=['full']),
         )
 
         # Add snapshot to visit3 (same date as visit2) and check that
         # the new snapshot is returned
         self.storage.snapshot_add(origin_id, visit3_id, self.complete_snapshot)
         self.assertEqual(self.complete_snapshot,
                          self.storage.snapshot_get_latest(origin_id))
 
     def test_stat_counters(self):
         expected_keys = ['content', 'directory',
                          'origin', 'person', 'revision']
 
         # Initially, all counters are 0
 
         self.storage.refresh_stat_counters()
         counters = self.storage.stat_counters()
         self.assertTrue(set(expected_keys) <= set(counters))
         for key in expected_keys:
             self.assertEqual(counters[key], 0)
 
         # Add a content. Only the content counter should increase.
 
         self.storage.content_add([self.cont])
 
         self.storage.refresh_stat_counters()
         counters = self.storage.stat_counters()
 
         self.assertTrue(set(expected_keys) <= set(counters))
         for key in expected_keys:
             if key != 'content':
                 self.assertEqual(counters[key], 0)
         self.assertEqual(counters['content'], 1)
 
         # Add other objects. Check their counter increased as well.
 
         origin_id = self.storage.origin_add_one(self.origin2)
         origin_visit1 = self.storage.origin_visit_add(
             origin_id,
             date=self.date_visit2)
         self.storage.snapshot_add(origin_id, origin_visit1['visit'],
                                   self.snapshot)
         self.storage.directory_add([self.dir])
         self.storage.revision_add([self.revision])
 
         self.storage.refresh_stat_counters()
         counters = self.storage.stat_counters()
         self.assertEqual(counters['content'], 1)
         self.assertEqual(counters['directory'], 1)
         self.assertEqual(counters['snapshot'], 1)
         self.assertEqual(counters['origin'], 1)
         self.assertEqual(counters['revision'], 1)
         self.assertEqual(counters['person'], 2)
 
     def test_content_find_ctime(self):
         cont = self.cont.copy()
         del cont['data']
         now = datetime.datetime.now(tz=datetime.timezone.utc)
         cont['ctime'] = now
         self.storage.content_add_metadata([cont])
 
         actually_present = self.storage.content_find({'sha1': cont['sha1']})
 
         self.assertEqual(actually_present, {
             'ctime': now,
             'sha1': cont['sha1'],
             'sha256': cont['sha256'],
             'sha1_git': cont['sha1_git'],
             'blake2s256': cont['blake2s256'],
             'length': cont['length'],
             'status': 'visible'
         })
 
     def test_content_find_with_present_content(self):
         # 1. with something to find
         cont = self.cont
         self.storage.content_add([cont])
 
         actually_present = self.storage.content_find({'sha1': cont['sha1']})
 
         actually_present.pop('ctime')
         self.assertEqual(actually_present, {
             'sha1': cont['sha1'],
             'sha256': cont['sha256'],
             'sha1_git': cont['sha1_git'],
             'blake2s256': cont['blake2s256'],
             'length': cont['length'],
             'status': 'visible'
         })
 
         # 2. with something to find
         actually_present = self.storage.content_find(
             {'sha1_git': cont['sha1_git']})
 
         actually_present.pop('ctime')
         self.assertEqual(actually_present, {
             'sha1': cont['sha1'],
             'sha256': cont['sha256'],
             'sha1_git': cont['sha1_git'],
             'blake2s256': cont['blake2s256'],
             'length': cont['length'],
             'status': 'visible'
         })
 
         # 3. with something to find
         actually_present = self.storage.content_find(
             {'sha256': cont['sha256']})
 
         actually_present.pop('ctime')
         self.assertEqual(actually_present, {
             'sha1': cont['sha1'],
             'sha256': cont['sha256'],
             'sha1_git': cont['sha1_git'],
             'blake2s256': cont['blake2s256'],
             'length': cont['length'],
             'status': 'visible'
         })
 
         # 4. with something to find
         actually_present = self.storage.content_find({
             'sha1': cont['sha1'],
             'sha1_git': cont['sha1_git'],
             'sha256': cont['sha256'],
             'blake2s256': cont['blake2s256'],
         })
 
         actually_present.pop('ctime')
         self.assertEqual(actually_present, {
             'sha1': cont['sha1'],
             'sha256': cont['sha256'],
             'sha1_git': cont['sha1_git'],
             'blake2s256': cont['blake2s256'],
             'length': cont['length'],
             'status': 'visible'
         })
 
     def test_content_find_with_non_present_content(self):
         # 1. with something that does not exist
         missing_cont = self.missing_cont
 
         actually_present = self.storage.content_find(
             {'sha1': missing_cont['sha1']})
 
         self.assertIsNone(actually_present)
 
         # 2. with something that does not exist
         actually_present = self.storage.content_find(
             {'sha1_git': missing_cont['sha1_git']})
 
         self.assertIsNone(actually_present)
 
         # 3. with something that does not exist
         actually_present = self.storage.content_find(
             {'sha256': missing_cont['sha256']})
 
         self.assertIsNone(actually_present)
 
     def test_content_find_bad_input(self):
         # 1. with bad input
         with self.assertRaises(ValueError):
             self.storage.content_find({})  # empty is bad
 
         # 2. with bad input
         with self.assertRaises(ValueError):
             self.storage.content_find(
                 {'unknown-sha1': 'something'})  # not the right key
 
     def test_object_find_by_sha1_git(self):
         sha1_gits = [b'00000000000000000000']
         expected = {
             b'00000000000000000000': [],
         }
 
         self.storage.content_add([self.cont])
         sha1_gits.append(self.cont['sha1_git'])
         expected[self.cont['sha1_git']] = [{
             'sha1_git': self.cont['sha1_git'],
             'type': 'content',
             'id': self.cont['sha1'],
         }]
 
         self.storage.directory_add([self.dir])
         sha1_gits.append(self.dir['id'])
         expected[self.dir['id']] = [{
             'sha1_git': self.dir['id'],
             'type': 'directory',
             'id': self.dir['id'],
         }]
 
         self.storage.revision_add([self.revision])
         sha1_gits.append(self.revision['id'])
         expected[self.revision['id']] = [{
             'sha1_git': self.revision['id'],
             'type': 'revision',
             'id': self.revision['id'],
         }]
 
         self.storage.release_add([self.release])
         sha1_gits.append(self.release['id'])
         expected[self.release['id']] = [{
             'sha1_git': self.release['id'],
             'type': 'release',
             'id': self.release['id'],
         }]
 
         ret = self.storage.object_find_by_sha1_git(sha1_gits)
         for val in ret.values():
             for obj in val:
                 del obj['object_id']
 
         self.assertEqual(expected, ret)
 
     def test_tool_add(self):
         tool = {
             'name': 'some-unknown-tool',
             'version': 'some-version',
             'configuration': {"debian-package": "some-package"},
         }
 
         actual_tool = self.storage.tool_get(tool)
         self.assertIsNone(actual_tool)  # does not exist
 
         # add it
         actual_tools = self.storage.tool_add([tool])
 
         self.assertEqual(len(actual_tools), 1)
         actual_tool = actual_tools[0]
         self.assertIsNotNone(actual_tool)  # now it exists
         new_id = actual_tool.pop('id')
         self.assertEqual(actual_tool, tool)
 
         actual_tools2 = self.storage.tool_add([tool])
         actual_tool2 = actual_tools2[0]
         self.assertIsNotNone(actual_tool2)  # now it exists
         new_id2 = actual_tool2.pop('id')
 
         self.assertEqual(new_id, new_id2)
         self.assertEqual(actual_tool, actual_tool2)
 
     def test_tool_add_multiple(self):
         tool = {
             'name': 'some-unknown-tool',
             'version': 'some-version',
             'configuration': {"debian-package": "some-package"},
         }
 
         actual_tools = list(self.storage.tool_add([tool]))
         self.assertEqual(len(actual_tools), 1)
 
         new_tools = [tool, {
             'name': 'yet-another-tool',
             'version': 'version',
             'configuration': {},
         }]
 
         actual_tools = self.storage.tool_add(new_tools)
         self.assertEqual(len(actual_tools), 2)
 
         # order not guaranteed, so we iterate over results to check
         for tool in actual_tools:
             _id = tool.pop('id')
             self.assertIsNotNone(_id)
             self.assertIn(tool, new_tools)
 
     def test_tool_get_missing(self):
         tool = {
             'name': 'unknown-tool',
             'version': '3.1.0rc2-31-ga2cbb8c',
             'configuration': {"command_line": "nomossa <filepath>"},
         }
 
         actual_tool = self.storage.tool_get(tool)
 
         self.assertIsNone(actual_tool)
 
     def test_tool_metadata_get_missing_context(self):
         tool = {
             'name': 'swh-metadata-translator',
             'version': '0.0.1',
             'configuration': {"context": "unknown-context"},
         }
 
         actual_tool = self.storage.tool_get(tool)
 
         self.assertIsNone(actual_tool)
 
     def test_tool_metadata_get(self):
         tool = {
             'name': 'swh-metadata-translator',
             'version': '0.0.1',
             'configuration': {"type": "local", "context": "npm"},
         }
 
         tools = self.storage.tool_add([tool])
         expected_tool = tools[0]
 
         # when
         actual_tool = self.storage.tool_get(tool)
 
         # then
         self.assertEqual(expected_tool, actual_tool)
 
     def test_metadata_provider_get(self):
         # given
         no_provider = self.storage.metadata_provider_get(6459456445615)
         self.assertIsNone(no_provider)
         # when
         provider_id = self.storage.metadata_provider_add(
             self.provider['name'],
             self.provider['type'],
             self.provider['url'],
             self.provider['metadata'])
 
         actual_provider = self.storage.metadata_provider_get(provider_id)
         expected_provider = {
             'provider_name': self.provider['name'],
             'provider_url': self.provider['url']
         }
         # then
         del actual_provider['id']
         self.assertTrue(actual_provider, expected_provider)
 
     def test_metadata_provider_get_by(self):
         # given
         no_provider = self.storage.metadata_provider_get_by({
             'provider_name': self.provider['name'],
             'provider_url': self.provider['url']
         })
         self.assertIsNone(no_provider)
         # when
         provider_id = self.storage.metadata_provider_add(
             self.provider['name'],
             self.provider['type'],
             self.provider['url'],
             self.provider['metadata'])
 
         actual_provider = self.storage.metadata_provider_get_by({
             'provider_name': self.provider['name'],
             'provider_url': self.provider['url']
         })
         # then
         self.assertTrue(provider_id, actual_provider['id'])
 
     def test_origin_metadata_add(self):
         # given
         origin_id = self.storage.origin_add([self.origin])[0]['id']
         origin_metadata0 = list(self.storage.origin_metadata_get_by(origin_id))
         self.assertTrue(len(origin_metadata0) == 0)
 
         tools = self.storage.tool_add([self.metadata_tool])
         tool = tools[0]
 
         self.storage.metadata_provider_add(
                            self.provider['name'],
                            self.provider['type'],
                            self.provider['url'],
                            self.provider['metadata'])
         provider = self.storage.metadata_provider_get_by({
                             'provider_name': self.provider['name'],
                             'provider_url': self.provider['url']
                       })
 
         # when adding for the same origin 2 metadatas
         self.storage.origin_metadata_add(
                     origin_id,
                     self.origin_metadata['discovery_date'],
                     provider['id'],
                     tool['id'],
                     self.origin_metadata['metadata'])
         actual_om1 = list(self.storage.origin_metadata_get_by(origin_id))
         # then
         self.assertEqual(len(actual_om1), 1)
         self.assertEqual(actual_om1[0]['origin_id'], origin_id)
 
     def test_origin_metadata_get(self):
         # given
         origin_id = self.storage.origin_add([self.origin])[0]['id']
         origin_id2 = self.storage.origin_add([self.origin2])[0]['id']
 
         self.storage.metadata_provider_add(self.provider['name'],
                                            self.provider['type'],
                                            self.provider['url'],
                                            self.provider['metadata'])
         provider = self.storage.metadata_provider_get_by({
                             'provider_name': self.provider['name'],
                             'provider_url': self.provider['url']
                    })
         tool = self.storage.tool_add([self.metadata_tool])[0]
         # when adding for the same origin 2 metadatas
         self.storage.origin_metadata_add(
                     origin_id,
                     self.origin_metadata['discovery_date'],
                     provider['id'],
                     tool['id'],
                     self.origin_metadata['metadata'])
         self.storage.origin_metadata_add(
                     origin_id2,
                     self.origin_metadata2['discovery_date'],
                     provider['id'],
                     tool['id'],
                     self.origin_metadata2['metadata'])
         self.storage.origin_metadata_add(
                     origin_id,
                     self.origin_metadata2['discovery_date'],
                     provider['id'],
                     tool['id'],
                     self.origin_metadata2['metadata'])
         all_metadatas = list(self.storage.origin_metadata_get_by(origin_id))
         metadatas_for_origin2 = list(self.storage.origin_metadata_get_by(
                                           origin_id2))
         expected_results = [{
             'origin_id': origin_id,
             'discovery_date': datetime.datetime(
                                 2017, 1, 1, 23, 0,
                                 tzinfo=datetime.timezone.utc),
             'metadata': {
                 'name': 'test_origin_metadata',
                 'version': '0.0.1'
             },
             'provider_id': provider['id'],
             'provider_name': 'hal',
             'provider_type': 'deposit-client',
             'provider_url': 'http:///hal/inria',
             'tool_id': tool['id']
         }, {
             'origin_id': origin_id,
             'discovery_date': datetime.datetime(
                                 2015, 1, 1, 23, 0,
                                 tzinfo=datetime.timezone.utc),
             'metadata': {
                 'name': 'test_origin_metadata',
                 'version': '0.0.1'
             },
             'provider_id': provider['id'],
             'provider_name': 'hal',
             'provider_type': 'deposit-client',
             'provider_url': 'http:///hal/inria',
             'tool_id': tool['id']
         }]
 
         # then
         self.assertEqual(len(all_metadatas), 2)
         self.assertEqual(len(metadatas_for_origin2), 1)
         self.assertCountEqual(all_metadatas, expected_results)
 
     def test_origin_metadata_get_by_provider_type(self):
         # given
         origin_id = self.storage.origin_add([self.origin])[0]['id']
         origin_id2 = self.storage.origin_add([self.origin2])[0]['id']
         provider1_id = self.storage.metadata_provider_add(
                            self.provider['name'],
                            self.provider['type'],
                            self.provider['url'],
                            self.provider['metadata'])
         provider1 = self.storage.metadata_provider_get_by({
                             'provider_name': self.provider['name'],
                             'provider_url': self.provider['url']
                    })
         self.assertEqual(provider1,
                          self.storage.metadata_provider_get(provider1_id))
 
         provider2_id = self.storage.metadata_provider_add(
                             'swMATH',
                             'registry',
                             'http://www.swmath.org/',
                             {'email': 'contact@swmath.org',
                              'license': 'All rights reserved'})
         provider2 = self.storage.metadata_provider_get_by({
                             'provider_name': 'swMATH',
                             'provider_url': 'http://www.swmath.org/'
                    })
         self.assertEqual(provider2,
                          self.storage.metadata_provider_get(provider2_id))
 
         # using the only tool now inserted in the data.sql, but for this
         # provider should be a crawler tool (not yet implemented)
         tool = self.storage.tool_add([self.metadata_tool])[0]
 
         # when adding for the same origin 2 metadatas
         self.storage.origin_metadata_add(
                     origin_id,
                     self.origin_metadata['discovery_date'],
                     provider1['id'],
                     tool['id'],
                     self.origin_metadata['metadata'])
         self.storage.origin_metadata_add(
                     origin_id2,
                     self.origin_metadata2['discovery_date'],
                     provider2['id'],
                     tool['id'],
                     self.origin_metadata2['metadata'])
         provider_type = 'registry'
         m_by_provider = list(self.storage.
                              origin_metadata_get_by(
                                 origin_id2,
                                 provider_type))
         for item in m_by_provider:
             if 'id' in item:
                 del item['id']
         expected_results = [{
             'origin_id': origin_id2,
             'discovery_date': datetime.datetime(
                                 2017, 1, 1, 23, 0,
                                 tzinfo=datetime.timezone.utc),
             'metadata': {
                 'name': 'test_origin_metadata',
                 'version': '0.0.1'
             },
             'provider_id': provider2['id'],
             'provider_name': 'swMATH',
             'provider_type': provider_type,
             'provider_url': 'http://www.swmath.org/',
             'tool_id': tool['id']
         }]
         # then
 
         self.assertEqual(len(m_by_provider), 1)
         self.assertEqual(m_by_provider, expected_results)
 
 
 class CommonPropTestStorage:
     def assert_contents_ok(self, expected_contents, actual_contents,
                            keys_to_check={'sha1', 'data'}):
         """Assert that a given list of contents matches on a given set of keys.
 
         """
         for k in keys_to_check:
             expected_list = sorted([c[k] for c in expected_contents])
             actual_list = sorted([c[k] for c in actual_contents])
             self.assertEqual(actual_list, expected_list)
 
     @given(gen_contents(min_size=1, max_size=4))
     def test_generate_content_get(self, contents):
         self.reset_storage_tables()
         # add contents to storage
         self.storage.content_add(contents)
 
         # input the list of sha1s we want from storage
         get_sha1s = [c['sha1'] for c in contents]
 
         # retrieve contents
         actual_contents = list(self.storage.content_get(get_sha1s))
 
         self.assert_contents_ok(contents, actual_contents)
 
     @given(gen_contents(min_size=1, max_size=4))
     def test_generate_content_get_metadata(self, contents):
         self.reset_storage_tables()
         # add contents to storage
         self.storage.content_add(contents)
 
         # input the list of sha1s we want from storage
         get_sha1s = [c['sha1'] for c in contents]
 
         # retrieve contents
         actual_contents = list(self.storage.content_get_metadata(get_sha1s))
 
         self.assertEqual(len(actual_contents), len(contents))
 
         # will check that all contents are retrieved correctly
         one_content = contents[0]
         # content_get_metadata does not return data
         keys_to_check = set(one_content.keys()) - {'data'}
         self.assert_contents_ok(contents, actual_contents,
                                 keys_to_check=keys_to_check)
 
     def test_generate_content_get_range_limit_none(self):
         """content_get_range call with wrong limit input should fail"""
         with self.assertRaises(ValueError) as e:
             self.storage.content_get_range(start=None, end=None, limit=None)
 
         self.assertEqual(e.exception.args, (
             'Development error: limit should not be None',))
 
     @given(gen_contents(min_size=1, max_size=4))
     def test_generate_content_get_range_no_limit(self, contents):
         """content_get_range returns contents within range provided"""
         self.reset_storage_tables()
         # add contents to storage
         self.storage.content_add(contents)
 
         # input the list of sha1s we want from storage
         get_sha1s = sorted([c['sha1'] for c in contents])
         start = get_sha1s[0]
         end = get_sha1s[-1]
 
         # retrieve contents
         actual_result = self.storage.content_get_range(start, end)
 
         actual_contents = actual_result['contents']
         actual_next = actual_result['next']
 
         self.assertEqual(len(contents), len(actual_contents))
         self.assertIsNone(actual_next)
 
         one_content = contents[0]
         keys_to_check = set(one_content.keys()) - {'data'}
         self.assert_contents_ok(contents, actual_contents, keys_to_check)
 
     @given(gen_contents(min_size=4, max_size=4))
     def test_generate_content_get_range_limit(self, contents):
         """content_get_range paginates results if limit exceeded"""
         self.reset_storage_tables()
         contents_map = {c['sha1']: c for c in contents}
 
         # add contents to storage
         self.storage.content_add(contents)
 
         # input the list of sha1s we want from storage
         get_sha1s = sorted([c['sha1'] for c in contents])
         start = get_sha1s[0]
         end = get_sha1s[-1]
 
         # retrieve contents limited to 3 results
         limited_results = len(contents) - 1
         actual_result = self.storage.content_get_range(start, end,
                                                        limit=limited_results)
 
         actual_contents = actual_result['contents']
         actual_next = actual_result['next']
 
         self.assertEqual(limited_results, len(actual_contents))
         self.assertIsNotNone(actual_next)
         self.assertEqual(actual_next, get_sha1s[-1])
 
         expected_contents = [contents_map[sha1] for sha1 in get_sha1s[:-1]]
         keys_to_check = set(contents[0].keys()) - {'data'}
         self.assert_contents_ok(expected_contents, actual_contents,
                                 keys_to_check)
 
         # retrieve next part
         actual_results2 = self.storage.content_get_range(start=end, end=end)
         actual_contents2 = actual_results2['contents']
         actual_next2 = actual_results2['next']
 
         self.assertEqual(1, len(actual_contents2))
         self.assertIsNone(actual_next2)
 
         self.assert_contents_ok([contents_map[actual_next]], actual_contents2,
 
                                 keys_to_check)
 
     def test_origin_get_invalid_id_legacy(self):
         invalid_origin_id = 1
 
         origin_info = self.storage.origin_get({'id': invalid_origin_id})
         self.assertIsNone(origin_info)
 
         origin_visits = list(self.storage.origin_visit_get(
             invalid_origin_id))
         self.assertEqual(origin_visits, [])
 
     def test_origin_get_invalid_id(self):
         origin_info = self.storage.origin_get([{'id': 1}, {'id': 2}])
         self.assertEqual(origin_info, [None, None])
 
         origin_visits = list(self.storage.origin_visit_get(1))
         self.assertEqual(origin_visits, [])
 
     @given(strategies.sets(origins().map(lambda x: tuple(x.to_dict().items())),
                            min_size=6, max_size=15))
     def test_origin_get_range(self, new_origins):
         self.reset_storage_tables()
         new_origins = list(map(dict, new_origins))
 
         nb_origins = len(new_origins)
 
         self.storage.origin_add(new_origins)
 
         origin_from = random.randint(1, nb_origins-1)
         origin_count = random.randint(1, nb_origins - origin_from)
 
         actual_origins = list(
             self.storage.origin_get_range(origin_from=origin_from,
                                           origin_count=origin_count))
 
         for origin in actual_origins:
             del origin['id']
 
         for origin in actual_origins:
             self.assertIn(origin, new_origins)
 
         origin_from = -1
         origin_count = 5
         origins = list(
             self.storage.origin_get_range(origin_from=origin_from,
                                           origin_count=origin_count))
         self.assertEqual(len(origins), origin_count)
 
         origin_from = 10000
         origins = list(
             self.storage.origin_get_range(origin_from=origin_from,
                                           origin_count=origin_count))
         self.assertEqual(len(origins), 0)
 
     def test_origin_count(self):
 
         new_origins = [
             {
                 'type': 'git',
                 'url': 'https://github.com/user1/repo1'
             },
             {
                 'type': 'git',
                 'url': 'https://github.com/user2/repo1'
             },
             {
                 'type': 'git',
                 'url': 'https://github.com/user3/repo1'
             },
             {
                 'type': 'git',
                 'url': 'https://gitlab.com/user1/repo1'
             },
             {
                 'type': 'git',
                 'url': 'https://gitlab.com/user2/repo1'
             }
         ]
 
         self.storage.origin_add(new_origins)
 
         self.assertEqual(self.storage.origin_count('github'), 3)
         self.assertEqual(self.storage.origin_count('gitlab'), 2)
         self.assertEqual(
             self.storage.origin_count('.*user.*', regexp=True), 5)
         self.assertEqual(
             self.storage.origin_count('.*user.*', regexp=False), 0)
         self.assertEqual(
             self.storage.origin_count('.*user1.*', regexp=True), 2)
         self.assertEqual(
             self.storage.origin_count('.*user1.*', regexp=False), 0)
 
     @given(strategies.lists(objects(), max_size=2))
     def test_add_arbitrary(self, objects):
         self.reset_storage_tables()
         for (obj_type, obj) in objects:
             obj = obj.to_dict()
             if obj_type == 'origin_visit':
                 origin_id = self.storage.origin_add_one(obj.pop('origin'))
                 if 'visit' in obj:
                     del obj['visit']
                 self.storage.origin_visit_add(origin_id, **obj)
             else:
                 method = getattr(self.storage, obj_type + '_add')
                 try:
                     method([obj])
                 except HashCollision:
                     pass
 
 
 @pytest.mark.db
 class TestLocalStorage(CommonTestStorage, StorageTestDbFixture,
                        unittest.TestCase):
     """Test the local storage"""
 
     # Can only be tested with local storage as you can't mock
     # datetimes for the remote server
     def test_fetch_history(self):
         origin = self.storage.origin_add_one(self.origin)
         with patch('datetime.datetime'):
             datetime.datetime.now.return_value = self.fetch_history_date
             fetch_history_id = self.storage.fetch_history_start(origin)
             datetime.datetime.now.assert_called_with(tz=datetime.timezone.utc)
 
         with patch('datetime.datetime'):
             datetime.datetime.now.return_value = self.fetch_history_end
             self.storage.fetch_history_end(fetch_history_id,
                                            self.fetch_history_data)
 
         fetch_history = self.storage.fetch_history_get(fetch_history_id)
         expected_fetch_history = self.fetch_history_data.copy()
 
         expected_fetch_history['id'] = fetch_history_id
         expected_fetch_history['origin'] = origin
         expected_fetch_history['date'] = self.fetch_history_date
         expected_fetch_history['duration'] = self.fetch_history_duration
 
         self.assertEqual(expected_fetch_history, fetch_history)
 
     # This test is only relevant on the local storage, with an actual
     # objstorage raising an exception
     def test_content_add_objstorage_exception(self):
         self.storage.objstorage.add = Mock(
             side_effect=Exception('mocked broken objstorage')
         )
 
         with self.assertRaises(Exception) as e:
             self.storage.content_add([self.cont])
 
         self.assertEqual(e.exception.args, ('mocked broken objstorage',))
         missing = list(self.storage.content_missing([self.cont]))
         self.assertEqual(missing, [self.cont['sha1']])
 
 
 @pytest.mark.db
 @pytest.mark.property_based
 class PropTestLocalStorage(CommonPropTestStorage, StorageTestDbFixture,
                            unittest.TestCase):
     pass
 
 
 class AlteringSchemaTest(TestStorageData, StorageTestDbFixture,
                          unittest.TestCase):
     """This class is dedicated for the rare case where the schema needs to
        be altered dynamically.
 
        Otherwise, the tests could be blocking when ran altogether.
 
     """
     def test_content_update(self):
         self.storage.journal_writer = None  # TODO, not supported
 
         cont = copy.deepcopy(self.cont)
 
         self.storage.content_add([cont])
         # alter the sha1_git for example
         cont['sha1_git'] = hash_to_bytes(
             '3a60a5275d0333bf13468e8b3dcab90f4046e654')
 
         self.storage.content_update([cont], keys=['sha1_git'])
 
         with self.storage.get_db().transaction() as cur:
             cur.execute('SELECT sha1, sha1_git, sha256, length, status'
                         ' FROM content WHERE sha1 = %s',
                         (cont['sha1'],))
             datum = cur.fetchone()
 
         self.assertEqual(
             (datum[0], datum[1], datum[2],
              datum[3], datum[4]),
             (cont['sha1'], cont['sha1_git'], cont['sha256'],
              cont['length'], 'visible'))
 
     def test_content_update_with_new_cols(self):
         self.storage.journal_writer = None  # TODO, not supported
 
         with self.storage.get_db().transaction() as cur:
             cur.execute("""alter table content
                            add column test text default null,
                            add column test2 text default null""")
 
         cont = copy.deepcopy(self.cont2)
         self.storage.content_add([cont])
         cont['test'] = 'value-1'
         cont['test2'] = 'value-2'
 
         self.storage.content_update([cont], keys=['test', 'test2'])
         with self.storage.get_db().transaction() as cur:
             cur.execute(
                 'SELECT sha1, sha1_git, sha256, length, status, test, test2'
                 ' FROM content WHERE sha1 = %s',
                 (cont['sha1'],))
 
             datum = cur.fetchone()
 
         self.assertEqual(
             (datum[0], datum[1], datum[2],
              datum[3], datum[4], datum[5], datum[6]),
             (cont['sha1'], cont['sha1_git'], cont['sha256'],
              cont['length'], 'visible', cont['test'], cont['test2']))
 
         with self.storage.get_db().transaction() as cur:
             cur.execute("""alter table content drop column test,
                            drop column test2""")
diff --git a/version.txt b/version.txt
index 969183e5..0c461625 100644
--- a/version.txt
+++ b/version.txt
@@ -1 +1 @@
-v0.0.138-0-gcf99702
\ No newline at end of file
+v0.0.139-0-g6510b5e
\ No newline at end of file