diff --git a/swh/provenance/algos/directory.py b/swh/provenance/algos/directory.py
--- a/swh/provenance/algos/directory.py
+++ b/swh/provenance/algos/directory.py
@@ -50,7 +50,7 @@
     """Flatten the known directories from ``start_id`` to ``end_id``."""
     current = start_id
     while current < end_id:
-        dirs = provenance.storage.directory_iter_not_flattenned(
+        dirs = provenance.storage.directory_iter_not_flattened(
             limit=100, start_id=current
         )
         if not dirs:
@@ -71,9 +71,9 @@
 ) -> None:
     for directory in directories:
         # Only flatten directories that are present in the provenance model, but not
-        # flattenned yet.
-        flattenned = provenance.directory_already_flattenned(directory)
-        if flattenned is not None and not flattenned:
+        # flattened yet.
+        flattened = provenance.directory_already_flattened(directory)
+        if flattened is not None and not flattened:
             directory_flatten(
                 provenance,
                 archive,
@@ -104,4 +104,4 @@
         for d_child in current.dirs:
             # Recursively walk the child directory.
             stack.append((d_child, os.path.join(prefix, d_child.name)))
-    provenance.directory_flag_as_flattenned(directory)
+    provenance.directory_flag_as_flattened(directory)
diff --git a/swh/provenance/interface.py b/swh/provenance/interface.py
--- a/swh/provenance/interface.py
+++ b/swh/provenance/interface.py
@@ -99,14 +99,14 @@
         """
         ...
 
-    def directory_already_flattenned(self, directory: DirectoryEntry) -> Optional[bool]:
-        """Check if the directory is already flattenned in the provenance model. If the
+    def directory_already_flattened(self, directory: DirectoryEntry) -> Optional[bool]:
+        """Check if the directory is already flattened in the provenance model. If the
         directory is unknown for the model, the methods returns None.
         """
         ...
 
-    def directory_flag_as_flattenned(self, directory: DirectoryEntry) -> None:
-        """Mark the directory as flattenned in the provenance model. If the
+    def directory_flag_as_flattened(self, directory: DirectoryEntry) -> None:
+        """Mark the directory as flattened in the provenance model. If the
         directory is unknown for the model, this method has no effect.
         """
         ...
diff --git a/swh/provenance/provenance.py b/swh/provenance/provenance.py
--- a/swh/provenance/provenance.py
+++ b/swh/provenance/provenance.py
@@ -4,6 +4,7 @@
 # See top-level LICENSE file for more information
 
 from datetime import datetime
+import hashlib
 import logging
 import os
 from types import TracebackType
@@ -252,7 +253,7 @@
                 )
 
         revs = {
-            sha1
+            sha1: RevisionData(date=None, origin=None)
             for sha1, date in self.cache["revision"]["data"].items()
             if sha1 in self.cache["revision"]["added"] and date is not None
         }
@@ -267,7 +268,7 @@
                 )
 
         paths = {
-            path
+            hashlib.sha1(path).digest(): path
             for _, _, path in self.cache["content_in_revision"]
             | self.cache["content_in_directory"]
             | self.cache["directory_in_revision"]
@@ -409,7 +410,7 @@
             (directory.id, revision.id, path_normalize(path))
         )
 
-    def directory_already_flattenned(self, directory: DirectoryEntry) -> Optional[bool]:
+    def directory_already_flattened(self, directory: DirectoryEntry) -> Optional[bool]:
         cache = self.cache["directory_flatten"]
         if directory.id not in cache:
             cache.setdefault(directory.id, None)
@@ -421,7 +422,7 @@
                 self.cache["directory"]["data"][directory.id] = dir.date
         return cache.get(directory.id)
 
-    def directory_flag_as_flattenned(self, directory: DirectoryEntry) -> None:
+    def directory_flag_as_flattened(self, directory: DirectoryEntry) -> None:
         self.cache["directory_flatten"][directory.id] = True
 
     def directory_get_date_in_isochrone_frontier(
diff --git a/swh/provenance/storage/interface.py b/swh/provenance/storage/interface.py
--- a/swh/provenance/storage/interface.py
+++ b/swh/provenance/storage/interface.py
@@ -9,7 +9,7 @@
 from datetime import datetime
 import enum
 from types import TracebackType
-from typing import Dict, Generator, Iterable, List, Optional, Set, Type, Union
+from typing import Dict, Generator, Iterable, List, Optional, Set, Type
 
 from typing_extensions import Protocol, runtime_checkable
 
@@ -136,11 +136,11 @@
         """
         ...
 
-    @remote_api_endpoint("directory_iter_not_flattenned")
-    def directory_iter_not_flattenned(
+    @remote_api_endpoint("directory_iter_not_flattened")
+    def directory_iter_not_flattened(
         self, limit: int, start_id: Sha1Git
     ) -> List[Sha1Git]:
-        """Retrieve the unflattenned directories after ``start_id`` up to ``limit`` entries."""
+        """Retrieve the unflattened directories after ``start_id`` up to ``limit`` entries."""
         ...
 
     @remote_api_endpoint("entity_get_all")
@@ -151,12 +151,12 @@
         ...
 
     @remote_api_endpoint("location_add")
-    def location_add(self, paths: Iterable[bytes]) -> bool:
+    def location_add(self, paths: Dict[Sha1Git, bytes]) -> bool:
         """Register the given `paths` in the storage."""
         ...
 
     @remote_api_endpoint("location_get_all")
-    def location_get_all(self) -> Set[bytes]:
+    def location_get_all(self) -> Dict[Sha1Git, bytes]:
         """Retrieve all paths present in the provenance model.
         This method is used only in tests."""
         ...
@@ -180,9 +180,7 @@
         ...
 
     @remote_api_endpoint("revision_add")
-    def revision_add(
-        self, revs: Union[Iterable[Sha1Git], Dict[Sha1Git, RevisionData]]
-    ) -> bool:
+    def revision_add(self, revs: Dict[Sha1Git, RevisionData]) -> bool:
         """Add revisions identified by sha1 ids, with optional associated date or origin
         (as paired in `revs`) to the provenance storage. Return a boolean stating if the
         information was successfully stored.
diff --git a/swh/provenance/storage/postgresql.py b/swh/provenance/storage/postgresql.py
--- a/swh/provenance/storage/postgresql.py
+++ b/swh/provenance/storage/postgresql.py
@@ -8,10 +8,11 @@
 from contextlib import contextmanager
 from datetime import datetime
 from functools import wraps
+from hashlib import sha1
 import itertools
 import logging
 from types import TracebackType
-from typing import Dict, Generator, Iterable, List, Optional, Set, Type, Union
+from typing import Dict, Generator, Iterable, List, Optional, Set, Type
 
 import psycopg2.extensions
 import psycopg2.extras
@@ -198,9 +199,9 @@
         return result
 
     @statsd.timed(
-        metric=STORAGE_DURATION_METRIC, tags={"method": "directory_iter_not_flattenned"}
+        metric=STORAGE_DURATION_METRIC, tags={"method": "directory_iter_not_flattened"}
     )
-    def directory_iter_not_flattenned(
+    def directory_iter_not_flattened(
         self, limit: int, start_id: Sha1Git
     ) -> List[Sha1Git]:
         sql = """
@@ -219,9 +220,9 @@
 
     @statsd.timed(metric=STORAGE_DURATION_METRIC, tags={"method": "location_add"})
     @handle_raise_on_commit
-    def location_add(self, paths: Iterable[bytes]) -> bool:
+    def location_add(self, paths: Dict[Sha1Git, bytes]) -> bool:
         if self.with_path():
-            values = [(path,) for path in paths]
+            values = [(path,) for path in paths.values()]
             if values:
                 sql = """
                     INSERT INTO location(path) VALUES %s
@@ -235,10 +236,10 @@
         return True
 
     @statsd.timed(metric=STORAGE_DURATION_METRIC, tags={"method": "location_get_all"})
-    def location_get_all(self) -> Set[bytes]:
+    def location_get_all(self) -> Dict[Sha1Git, bytes]:
         with self.transaction(readonly=True) as cursor:
             cursor.execute("SELECT location.path AS path FROM location")
-            return {row["path"] for row in cursor}
+            return {sha1(row["path"]).digest(): row["path"] for row in cursor}
 
     @statsd.timed(metric=STORAGE_DURATION_METRIC, tags={"method": "origin_add"})
     @handle_raise_on_commit
@@ -284,14 +285,9 @@
 
     @statsd.timed(metric=STORAGE_DURATION_METRIC, tags={"method": "revision_add"})
     @handle_raise_on_commit
-    def revision_add(
-        self, revs: Union[Iterable[Sha1Git], Dict[Sha1Git, RevisionData]]
-    ) -> bool:
-        if isinstance(revs, dict):
+    def revision_add(self, revs: Dict[Sha1Git, RevisionData]) -> bool:
+        if revs:
             data = [(sha1, rev.date, rev.origin) for sha1, rev in revs.items()]
-        else:
-            data = [(sha1, None, None) for sha1 in revs]
-        if data:
             sql = """
                 INSERT INTO revision(sha1, date, origin)
                   (SELECT V.rev AS sha1, V.date::timestamptz AS date, O.id AS origin
diff --git a/swh/provenance/storage/rabbitmq/client.py b/swh/provenance/storage/rabbitmq/client.py
--- a/swh/provenance/storage/rabbitmq/client.py
+++ b/swh/provenance/storage/rabbitmq/client.py
@@ -71,6 +71,7 @@
         if isinstance(data, dict):
             items = set(data.items())
         else:
+            # TODO this is probably not used any more
             items = {(item,) for item in data}
         for id, *rest in items:
             key = ProvenanceStorageRabbitMQServer.get_routing_key(id, meth_name)
diff --git a/swh/provenance/storage/rabbitmq/server.py b/swh/provenance/storage/rabbitmq/server.py
--- a/swh/provenance/storage/rabbitmq/server.py
+++ b/swh/provenance/storage/rabbitmq/server.py
@@ -480,7 +480,7 @@
         elif meth_name == "directory_add":
             return resolve_directory
         elif meth_name == "location_add":
-            return lambda data: set(data)  # just remove duplicates
+            return lambda data: dict(data)
         elif meth_name == "origin_add":
             return lambda data: dict(data)  # last processed value is good enough
         elif meth_name == "revision_add":
diff --git a/swh/provenance/tests/test_directory_flatten.py b/swh/provenance/tests/test_directory_flatten.py
--- a/swh/provenance/tests/test_directory_flatten.py
+++ b/swh/provenance/tests/test_directory_flatten.py
@@ -52,8 +52,8 @@
 
     # this query forces the directory date to be retrieved from the storage and cached
     # (otherwise, the flush below won't update the directory flatten flag)
-    flattenned = provenance.directory_already_flattenned(directory)
-    assert flattenned is not None and not flattenned
+    flattened = provenance.directory_already_flattened(directory)
+    assert flattened is not None and not flattened
 
     return date, directory, content1, content2
 
diff --git a/swh/provenance/tests/test_provenance_storage.py b/swh/provenance/tests/test_provenance_storage.py
--- a/swh/provenance/tests/test_provenance_storage.py
+++ b/swh/provenance/tests/test_provenance_storage.py
@@ -4,6 +4,7 @@
 # See top-level LICENSE file for more information
 
 from datetime import datetime, timezone
+import hashlib
 import inspect
 import os
 from typing import Any, Dict, Iterable, Optional, Set, Tuple
@@ -99,13 +100,17 @@
 
         # Add all names of entries present in the directories of the current repo as paths
         # to the storage. Then check that the returned results when querying are the same.
-        paths = {entry["name"] for dir in data["directory"] for entry in dir["entries"]}
+        paths = {
+            hashlib.sha1(entry["name"]).digest(): entry["name"]
+            for dir in data["directory"]
+            for entry in dir["entries"]
+        }
         assert provenance_storage.location_add(paths)
 
         if provenance_storage.with_path():
             assert provenance_storage.location_get_all() == paths
         else:
-            assert provenance_storage.location_get_all() == set()
+            assert not provenance_storage.location_get_all()
 
     @pytest.mark.origin_layer
     def test_provenance_storage_origin(
@@ -143,22 +148,22 @@
         # Origin must be inserted in advance.
         assert provenance_storage.origin_add({origin.id: origin.url})
 
-        revs = {rev["id"] for idx, rev in enumerate(data["revision"]) if idx % 6 == 0}
+        revs = {rev["id"] for idx, rev in enumerate(data["revision"])}
         rev_data = {
             rev["id"]: RevisionData(
                 date=ts2dt(rev["date"]) if idx % 2 != 0 else None,
                 origin=origin.id if idx % 3 != 0 else None,
             )
             for idx, rev in enumerate(data["revision"])
-            if idx % 6 != 0
         }
         assert revs
-        assert provenance_storage.revision_add(revs)
         assert provenance_storage.revision_add(rev_data)
-        assert provenance_storage.revision_get(set(rev_data.keys())) == rev_data
-        assert provenance_storage.entity_get_all(EntityType.REVISION) == revs | set(
-            rev_data.keys()
-        )
+        assert provenance_storage.revision_get(set(rev_data.keys())) == {
+            k: v
+            for (k, v) in rev_data.items()
+            if v.date is not None or v.origin is not None
+        }
+        assert provenance_storage.entity_get_all(EntityType.REVISION) == set(rev_data)
 
     def test_provenance_storage_relation_revision_layer(
         self,
@@ -476,7 +481,12 @@
         assert entity_add(storage, EntityType(dst), dsts)
     if storage.with_path():
         assert storage.location_add(
-            {rel.path for rels in data.values() for rel in rels if rel.path is not None}
+            {
+                hashlib.sha1(rel.path).digest(): rel.path
+                for rels in data.values()
+                for rel in rels
+                if rel.path is not None
+            }
         )
 
     assert data
diff --git a/swh/provenance/tests/test_revision_content_layer.py b/swh/provenance/tests/test_revision_content_layer.py
--- a/swh/provenance/tests/test_revision_content_layer.py
+++ b/swh/provenance/tests/test_revision_content_layer.py
@@ -223,7 +223,7 @@
                 ).difference(prev_directories)
             ]
             for directory in directories:
-                assert not provenance.directory_already_flattenned(directory)
+                assert not provenance.directory_already_flattened(directory)
             directory_add(provenance, archive, directories)
 
         # each "entry" in the synth file is one new revision
@@ -317,9 +317,9 @@
             rows["location"] |= set(x["path"].encode() for x in synth_rev["R_C"])
             rows["location"] |= set(x["path"].encode() for x in synth_rev["D_C"])
             rows["location"] |= set(x["path"].encode() for x in synth_rev["R_D"])
-            assert rows["location"] == provenance.storage.location_get_all(), synth_rev[
-                "msg"
-            ]
+            assert rows["location"] == set(
+                provenance.storage.location_get_all().values()
+            ), synth_rev["msg"]
 
 
 @pytest.mark.parametrize(