diff --git a/mypy.ini b/mypy.ini
index e7ee430..9da0730 100644
--- a/mypy.ini
+++ b/mypy.ini
@@ -1,33 +1,33 @@
 [mypy]
 namespace_packages = True
 
 # due to the conditional import logic on swh.journal, in some cases a specific
-# type: ignore is neede, in other it isn't...
+# type: ignore is needed, in other it isn't...
 warn_unused_ignores = False
 
 # support for sqlalchemy magic: see https://github.com/dropbox/sqlalchemy-stubs
 plugins = sqlmypy
 
 
 # 3rd party libraries without stubs (yet)
 
 # only shipped indirectly via hypothesis
 [mypy-django.*]
 ignore_missing_imports = True
 
 [mypy-pkg_resources.*]
 ignore_missing_imports = True
 
 [mypy-psycopg2.*]
 ignore_missing_imports = True
 
 [mypy-pytest.*]
 ignore_missing_imports = True
 
 # temporary work-around for landing typing support in spite of the current
 # journal<->storage dependency loop
 [mypy-swh.journal.*]
 ignore_missing_imports = True
 
 [mypy-pytest_postgresql.*]
 ignore_missing_imports = True
diff --git a/sql/upgrades/032.sql b/sql/upgrades/032.sql
index 3804909..d245c13 100644
--- a/sql/upgrades/032.sql
+++ b/sql/upgrades/032.sql
@@ -1,121 +1,121 @@
 -- SWH DB schema upgrade
 -- from_version: 30
 -- to_version: 32
--- description: Reading data improvment on directory and release data.
+-- description: Reading data improvement on directory and release data.
 
 insert into dbversion(version, release, description)
       values(32, now(), 'Work In Progress');
 
 CREATE FUNCTION swh_mktemp_release_get()
     returns void
     language sql
 as $$
     create temporary table tmp_release_get(
       id sha1_git primary key
     ) on commit drop;
 $$;
 
 -- Detailed entry for a release
 CREATE TYPE release_entry AS
 (
   id          sha1_git,
   revision    sha1_git,
   date        timestamptz,
   date_offset smallint,
   name        text,
   comment     bytea,
   synthetic   boolean,
   author_name bytea,
   author_email bytea
 );
 
 -- Detailed entry for release
 CREATE OR REPLACE FUNCTION swh_release_get()
     returns setof release_entry
     language plpgsql
 as $$
 begin
     return query
         select r.id, r.revision, r.date, r.date_offset, r.name, r.comment,
                r.synthetic, p.name as author_name, p.email as author_email
         from tmp_release_get t
         inner join release r on t.id = r.id
         inner join person p on p.id = r.author;
     return;
 end
 $$;
 
 DROP TYPE IF EXISTS directory_entry CASCADE;
 
 -- a directory listing entry with all the metadata
 --
 -- can be used to list a directory, and retrieve all the data in one go.
 CREATE TYPE directory_entry AS
 (
   dir_id   sha1_git,     -- id of the parent directory
   type     directory_entry_type,  -- type of entry
   target   sha1_git,     -- id of target
   name     unix_path,    -- path name, relative to containing dir
   perms    file_perms,   -- unix-like permissions
   status   content_status,  -- visible or absent
   sha1     sha1,            -- content if sha1 if type is not dir
   sha1_git sha1_git,        -- content's sha1 git if type is not dir
   sha256   sha256           -- content's sha256 if type is not dir
 );
 
 -- List a single level of directory walked_dir_id
 -- FIXME: order by name is not correct. For git, we need to order by
 -- lexicographic order but as if a trailing / is present in directory
 -- name
 create or replace function swh_directory_walk_one(walked_dir_id sha1_git)
     returns setof directory_entry
     language sql
     stable
 as $$
     with dir as (
 	select id as dir_id, dir_entries, file_entries, rev_entries
 	from directory
 	where id = walked_dir_id),
     ls_d as (select dir_id, unnest(dir_entries) as entry_id from dir),
     ls_f as (select dir_id, unnest(file_entries) as entry_id from dir),
     ls_r as (select dir_id, unnest(rev_entries) as entry_id from dir)
     (select dir_id, 'dir'::directory_entry_type as type,
             e.target, e.name, e.perms, NULL::content_status,
             NULL::sha1, NULL::sha1_git, NULL::sha256
      from ls_d
      left join directory_entry_dir e on ls_d.entry_id = e.id)
     union
     (select dir_id, 'file'::directory_entry_type as type,
             e.target, e.name, e.perms, c.status,
             c.sha1, c.sha1_git, c.sha256
      from ls_f
      left join directory_entry_file e on ls_f.entry_id = e.id
      left join content c on e.target = c.sha1_git)
     union
     (select dir_id, 'rev'::directory_entry_type as type,
             e.target, e.name, e.perms, NULL::content_status,
             NULL::sha1, NULL::sha1_git, NULL::sha256
      from ls_r
      left join directory_entry_rev e on ls_r.entry_id = e.id)
     order by name;
 $$;
 
 -- List recursively the content of a directory
 create or replace function swh_directory_walk(walked_dir_id sha1_git)
     returns setof directory_entry
     language sql
     stable
 as $$
     with recursive entries as (
         select dir_id, type, target, name, perms, status, sha1, sha1_git,
                sha256
         from swh_directory_walk_one(walked_dir_id)
         union all
         select dir_id, type, target, (dirname || '/' || name)::unix_path as name,
                perms, status, sha1, sha1_git, sha256
         from (select (swh_directory_walk_one(dirs.target)).*, dirs.name as dirname
               from (select target, name from entries where type = 'dir') as dirs) as with_parent
     )
     select dir_id, type, target, name, perms, status, sha1, sha1_git, sha256
     from entries
 $$;
diff --git a/swh/storage/sql/40-swh-func.sql b/swh/storage/sql/40-swh-func.sql
index 7c1a88d..46b3ab2 100644
--- a/swh/storage/sql/40-swh-func.sql
+++ b/swh/storage/sql/40-swh-func.sql
@@ -1,1121 +1,1121 @@
 create or replace function hash_sha1(text)
        returns text
 as $$
    select encode(digest($1, 'sha1'), 'hex')
 $$ language sql strict immutable;
 
 comment on function hash_sha1(text) is 'Compute SHA1 hash as text';
 
 -- create a temporary table called tmp_TBLNAME, mimicking existing table
 -- TBLNAME
 --
 -- Args:
---     tblname: name of the table to mimick
+--     tblname: name of the table to mimic
 create or replace function swh_mktemp(tblname regclass)
     returns void
     language plpgsql
 as $$
 begin
     execute format('
 	create temporary table tmp_%1$I
 	    (like %1$I including defaults)
 	    on commit drop;
       alter table tmp_%1$I drop column if exists object_id;
 	', tblname);
     return;
 end
 $$;
 
 -- create a temporary table for directory entries called tmp_TBLNAME,
 -- mimicking existing table TBLNAME with an extra dir_id (sha1_git)
 -- column, and dropping the id column.
 --
 -- This is used to create the tmp_directory_entry_<foo> tables.
 --
 -- Args:
---     tblname: name of the table to mimick
+--     tblname: name of the table to mimic
 create or replace function swh_mktemp_dir_entry(tblname regclass)
     returns void
     language plpgsql
 as $$
 begin
     execute format('
 	create temporary table tmp_%1$I
 	    (like %1$I including defaults, dir_id sha1_git)
 	    on commit drop;
         alter table tmp_%1$I drop column id;
 	', tblname);
     return;
 end
 $$;
 
 
 -- create a temporary table for revisions called tmp_revisions,
 -- mimicking existing table revision, replacing the foreign keys to
 -- people with an email and name field
 --
 create or replace function swh_mktemp_revision()
     returns void
     language sql
 as $$
     create temporary table tmp_revision (
         like revision including defaults,
         author_fullname bytea,
         author_name bytea,
         author_email bytea,
         committer_fullname bytea,
         committer_name bytea,
         committer_email bytea
     ) on commit drop;
     alter table tmp_revision drop column author;
     alter table tmp_revision drop column committer;
     alter table tmp_revision drop column object_id;
 $$;
 
 
 -- create a temporary table for releases called tmp_release,
 -- mimicking existing table release, replacing the foreign keys to
 -- people with an email and name field
 --
 create or replace function swh_mktemp_release()
     returns void
     language sql
 as $$
     create temporary table tmp_release (
         like release including defaults,
         author_fullname bytea,
         author_name bytea,
         author_email bytea
     ) on commit drop;
     alter table tmp_release drop column author;
     alter table tmp_release drop column object_id;
 $$;
 
 -- create a temporary table for the branches of a snapshot
 create or replace function swh_mktemp_snapshot_branch()
     returns void
     language sql
 as $$
   create temporary table tmp_snapshot_branch (
       name bytea not null,
       target bytea,
       target_type snapshot_target
   ) on commit drop;
 $$;
 
 create or replace function swh_mktemp_tool()
     returns void
     language sql
 as $$
     create temporary table tmp_tool (
       like tool including defaults
     ) on commit drop;
     alter table tmp_tool drop column id;
 $$;
 
 
 -- a content signature is a set of cryptographic checksums that we use to
 -- uniquely identify content, for the purpose of verifying if we already have
 -- some content or not during content injection
 create type content_signature as (
     sha1       sha1,
     sha1_git   sha1_git,
     sha256     sha256,
     blake2s256 blake2s256
 );
 
 
 -- check which entries of tmp_skipped_content are missing from skipped_content
 --
 -- operates in bulk: 0. swh_mktemp(skipped_content), 1. COPY to tmp_skipped_content,
 -- 2. call this function
 create or replace function swh_skipped_content_missing()
     returns setof content_signature
     language plpgsql
 as $$
 begin
     return query
 	select sha1, sha1_git, sha256, blake2s256 from tmp_skipped_content t
 	where not exists
 	(select 1 from skipped_content s where
 	    s.sha1 is not distinct from t.sha1 and
 	    s.sha1_git is not distinct from t.sha1_git and
 	    s.sha256 is not distinct from t.sha256);
     return;
 end
 $$;
 
 
 -- Look up content based on one or several different checksums. Return all
 -- content information if the content is found; a NULL row otherwise.
 --
 -- At least one checksum should be not NULL. If several are not NULL, they will
 -- be AND-ed together in the lookup query.
 --
 -- Note: this function is meant to be used to look up individual contents
 -- (e.g., for the web app), for batch lookup of missing content (e.g., to be
 -- added) see swh_content_missing
 create or replace function swh_content_find(
     sha1       sha1       default NULL,
     sha1_git   sha1_git   default NULL,
     sha256     sha256     default NULL,
     blake2s256 blake2s256 default NULL
 )
     returns content
     language plpgsql
 as $$
 declare
     con content;
     filters text[] := array[] :: text[];  -- AND-clauses used to filter content
     q text;
 begin
     if sha1 is not null then
         filters := filters || format('sha1 = %L', sha1);
     end if;
     if sha1_git is not null then
         filters := filters || format('sha1_git = %L', sha1_git);
     end if;
     if sha256 is not null then
         filters := filters || format('sha256 = %L', sha256);
     end if;
     if blake2s256 is not null then
         filters := filters || format('blake2s256 = %L', blake2s256);
     end if;
 
     if cardinality(filters) = 0 then
         return null;
     else
         q = format('select * from content where %s',
                    array_to_string(filters, ' and '));
         execute q into con;
 	return con;
     end if;
 end
 $$;
 
 
 -- add tmp_content entries to content, skipping duplicates
 --
 -- operates in bulk: 0. swh_mktemp(content), 1. COPY to tmp_content,
 -- 2. call this function
 create or replace function swh_content_add()
     returns void
     language plpgsql
 as $$
 begin
     insert into content (sha1, sha1_git, sha256, blake2s256, length, status, ctime)
         select distinct sha1, sha1_git, sha256, blake2s256, length, status, ctime from tmp_content;
     return;
 end
 $$;
 
 
 -- add tmp_skipped_content entries to skipped_content, skipping duplicates
 --
 -- operates in bulk: 0. swh_mktemp(skipped_content), 1. COPY to tmp_skipped_content,
 -- 2. call this function
 create or replace function swh_skipped_content_add()
     returns void
     language plpgsql
 as $$
 begin
     insert into skipped_content (sha1, sha1_git, sha256, blake2s256, length, status, reason, origin)
         select distinct sha1, sha1_git, sha256, blake2s256, length, status, reason, origin
 	from tmp_skipped_content
 	where (coalesce(sha1, ''), coalesce(sha1_git, ''), coalesce(sha256, '')) in (
             select coalesce(sha1, ''), coalesce(sha1_git, ''), coalesce(sha256, '')
             from swh_skipped_content_missing()
         );
         -- TODO XXX use postgres 9.5 "UPSERT" support here, when available.
         -- Specifically, using "INSERT .. ON CONFLICT IGNORE" we can avoid
         -- the extra swh_content_missing() query here.
     return;
 end
 $$;
 
 -- Update content entries from temporary table.
 -- (columns are potential new columns added to the schema, this cannot be empty)
 --
 create or replace function swh_content_update(columns_update text[])
     returns void
     language plpgsql
 as $$
 declare
    query text;
    tmp_array text[];
 begin
     if array_length(columns_update, 1) = 0 then
         raise exception 'Please, provide the list of column names to update.';
     end if;
 
     tmp_array := array(select format('%1$s=t.%1$s', unnest) from unnest(columns_update));
 
     query = format('update content set %s
                     from tmp_content t where t.sha1 = content.sha1',
                     array_to_string(tmp_array, ', '));
 
     execute query;
 
     return;
 end
 $$;
 
 comment on function swh_content_update(text[]) IS 'Update existing content''s columns';
 
 -- check which entries of tmp_directory are missing from directory
 --
 -- operates in bulk: 0. swh_mktemp(directory), 1. COPY to tmp_directory,
 -- 2. call this function
 create or replace function swh_directory_missing()
     returns setof sha1_git
     language plpgsql
 as $$
 begin
     return query
 	select id from tmp_directory t
 	where not exists (
 	    select 1 from directory d
 	    where d.id = t.id);
     return;
 end
 $$;
 
 
 create type directory_entry_type as enum('file', 'dir', 'rev');
 
 
 -- Add tmp_directory_entry_* entries to directory_entry_* and directory,
 -- skipping duplicates in directory_entry_*.  This is a generic function that
 -- works on all kind of directory entries.
 --
 -- operates in bulk: 0. swh_mktemp_dir_entry('directory_entry_*'), 1 COPY to
 -- tmp_directory_entry_*, 2. call this function
 --
 -- Assumption: this function is used in the same transaction that inserts the
 -- context directory in table "directory".
 create or replace function swh_directory_entry_add(typ directory_entry_type)
     returns void
     language plpgsql
 as $$
 begin
     execute format('
     insert into directory_entry_%1$s (target, name, perms)
     select distinct t.target, t.name, t.perms
     from tmp_directory_entry_%1$s t
     where not exists (
     select 1
     from directory_entry_%1$s i
     where t.target = i.target and t.name = i.name and t.perms = i.perms)
    ', typ);
 
     execute format('
     with new_entries as (
 	select t.dir_id, array_agg(i.id) as entries
 	from tmp_directory_entry_%1$s t
 	inner join directory_entry_%1$s i
 	using (target, name, perms)
 	group by t.dir_id
     )
     update tmp_directory as d
     set %1$s_entries = new_entries.entries
     from new_entries
     where d.id = new_entries.dir_id
     ', typ);
 
     return;
 end
 $$;
 
 -- Insert the data from tmp_directory, tmp_directory_entry_file,
 -- tmp_directory_entry_dir, tmp_directory_entry_rev into their final
 -- tables.
 --
 -- Prerequisites:
 --  directory ids in tmp_directory
 --  entries in tmp_directory_entry_{file,dir,rev}
 --
 create or replace function swh_directory_add()
     returns void
     language plpgsql
 as $$
 begin
     perform swh_directory_entry_add('file');
     perform swh_directory_entry_add('dir');
     perform swh_directory_entry_add('rev');
 
     insert into directory
     select * from tmp_directory t
     where not exists (
         select 1 from directory d
 	where d.id = t.id);
 
     return;
 end
 $$;
 
 -- a directory listing entry with all the metadata
 --
 -- can be used to list a directory, and retrieve all the data in one go.
 create type directory_entry as
 (
   dir_id   sha1_git,     -- id of the parent directory
   type     directory_entry_type,  -- type of entry
   target   sha1_git,     -- id of target
   name     unix_path,    -- path name, relative to containing dir
   perms    file_perms,   -- unix-like permissions
   status   content_status,  -- visible or absent
   sha1     sha1,            -- content if sha1 if type is not dir
   sha1_git sha1_git,        -- content's sha1 git if type is not dir
   sha256   sha256,          -- content's sha256 if type is not dir
   length   bigint           -- content length if type is not dir
 );
 
 
 -- List a single level of directory walked_dir_id
 -- FIXME: order by name is not correct. For git, we need to order by
 -- lexicographic order but as if a trailing / is present in directory
 -- name
 create or replace function swh_directory_walk_one(walked_dir_id sha1_git)
     returns setof directory_entry
     language sql
     stable
 as $$
     with dir as (
 	select id as dir_id, dir_entries, file_entries, rev_entries
 	from directory
 	where id = walked_dir_id),
     ls_d as (select dir_id, unnest(dir_entries) as entry_id from dir),
     ls_f as (select dir_id, unnest(file_entries) as entry_id from dir),
     ls_r as (select dir_id, unnest(rev_entries) as entry_id from dir)
     (select dir_id, 'dir'::directory_entry_type as type,
             e.target, e.name, e.perms, NULL::content_status,
             NULL::sha1, NULL::sha1_git, NULL::sha256, NULL::bigint
      from ls_d
      left join directory_entry_dir e on ls_d.entry_id = e.id)
     union
     (select dir_id, 'file'::directory_entry_type as type,
             e.target, e.name, e.perms, c.status,
             c.sha1, c.sha1_git, c.sha256, c.length
      from ls_f
      left join directory_entry_file e on ls_f.entry_id = e.id
      left join content c on e.target = c.sha1_git)
     union
     (select dir_id, 'rev'::directory_entry_type as type,
             e.target, e.name, e.perms, NULL::content_status,
             NULL::sha1, NULL::sha1_git, NULL::sha256, NULL::bigint
      from ls_r
      left join directory_entry_rev e on ls_r.entry_id = e.id)
     order by name;
 $$;
 
 -- List recursively the revision directory arborescence
 create or replace function swh_directory_walk(walked_dir_id sha1_git)
     returns setof directory_entry
     language sql
     stable
 as $$
     with recursive entries as (
         select dir_id, type, target, name, perms, status, sha1, sha1_git,
                sha256, length
         from swh_directory_walk_one(walked_dir_id)
         union all
         select dir_id, type, target, (dirname || '/' || name)::unix_path as name,
                perms, status, sha1, sha1_git, sha256, length
         from (select (swh_directory_walk_one(dirs.target)).*, dirs.name as dirname
               from (select target, name from entries where type = 'dir') as dirs) as with_parent
     )
     select dir_id, type, target, name, perms, status, sha1, sha1_git, sha256, length
     from entries
 $$;
 
 create or replace function swh_revision_walk(revision_id sha1_git)
   returns setof directory_entry
   language sql
   stable
 as $$
   select dir_id, type, target, name, perms, status, sha1, sha1_git, sha256, length
   from swh_directory_walk((select directory from revision where id=revision_id))
 $$;
 
 COMMENT ON FUNCTION swh_revision_walk(sha1_git) IS 'Recursively list the revision targeted directory arborescence';
 
 
 -- Find a directory entry by its path
 create or replace function swh_find_directory_entry_by_path(
     walked_dir_id sha1_git,
     dir_or_content_path bytea[])
     returns directory_entry
     language plpgsql
 as $$
 declare
     end_index integer;
     paths bytea default '';
     path bytea;
     res bytea[];
     r record;
 begin
     end_index := array_upper(dir_or_content_path, 1);
     res[1] := walked_dir_id;
 
     for i in 1..end_index
     loop
         path := dir_or_content_path[i];
         -- concatenate path for patching the name in the result record (if we found it)
         if i = 1 then
             paths = path;
         else
             paths := paths || '/' || path;  -- concatenate paths
         end if;
 
         if i <> end_index then
             select *
             from swh_directory_walk_one(res[i] :: sha1_git)
             where name=path
             and type = 'dir'
             limit 1 into r;
         else
             select *
             from swh_directory_walk_one(res[i] :: sha1_git)
             where name=path
             limit 1 into r;
         end if;
 
         -- find the path
         if r is null then
            return null;
         else
             -- store the next dir to lookup the next local path from
             res[i+1] := r.target;
         end if;
     end loop;
 
     -- at this moment, r is the result. Patch its 'name' with the full path before returning it.
     r.name := paths;
     return r;
 end
 $$;
 
 -- List all revision IDs starting from a given revision, going back in time
 --
 -- TODO ordering: should be breadth-first right now (what do we want?)
 -- TODO ordering: ORDER BY parent_rank somewhere?
 create or replace function swh_revision_list(root_revisions bytea[], num_revs bigint default NULL)
     returns table (id sha1_git, parents bytea[])
     language sql
     stable
 as $$
     with recursive full_rev_list(id) as (
         (select id from revision where id = ANY(root_revisions))
         union
         (select h.parent_id
          from revision_history as h
          join full_rev_list on h.id = full_rev_list.id)
     ),
     rev_list as (select id from full_rev_list limit num_revs)
     select rev_list.id as id,
            array(select rh.parent_id::bytea
                  from revision_history rh
                  where rh.id = rev_list.id
                  order by rh.parent_rank
                 ) as parent
     from rev_list;
 $$;
 
 -- List all the children of a given revision
 create or replace function swh_revision_list_children(root_revisions bytea[], num_revs bigint default NULL)
     returns table (id sha1_git, parents bytea[])
     language sql
     stable
 as $$
     with recursive full_rev_list(id) as (
         (select id from revision where id = ANY(root_revisions))
         union
         (select h.id
          from revision_history as h
          join full_rev_list on h.parent_id = full_rev_list.id)
     ),
     rev_list as (select id from full_rev_list limit num_revs)
     select rev_list.id as id,
            array(select rh.parent_id::bytea
                  from revision_history rh
                  where rh.id = rev_list.id
                  order by rh.parent_rank
                 ) as parent
     from rev_list;
 $$;
 
 
 -- Detailed entry for a revision
 create type revision_entry as
 (
   id                             sha1_git,
   date                           timestamptz,
   date_offset                    smallint,
   date_neg_utc_offset            boolean,
   committer_date                 timestamptz,
   committer_date_offset          smallint,
   committer_date_neg_utc_offset  boolean,
   type                           revision_type,
   directory                      sha1_git,
   message                        bytea,
   author_id                      bigint,
   author_fullname                bytea,
   author_name                    bytea,
   author_email                   bytea,
   committer_id                   bigint,
   committer_fullname             bytea,
   committer_name                 bytea,
   committer_email                bytea,
   metadata                       jsonb,
   synthetic                      boolean,
   parents                        bytea[],
   object_id                      bigint
 );
 
 
 -- "git style" revision log. Similar to swh_revision_list(), but returning all
 -- information associated to each revision, and expanding authors/committers
 create or replace function swh_revision_log(root_revisions bytea[], num_revs bigint default NULL)
     returns setof revision_entry
     language sql
     stable
 as $$
     select t.id, r.date, r.date_offset, r.date_neg_utc_offset,
            r.committer_date, r.committer_date_offset, r.committer_date_neg_utc_offset,
            r.type, r.directory, r.message,
            a.id, a.fullname, a.name, a.email,
            c.id, c.fullname, c.name, c.email,
            r.metadata, r.synthetic, t.parents, r.object_id
     from swh_revision_list(root_revisions, num_revs) as t
     left join revision r on t.id = r.id
     left join person a on a.id = r.author
     left join person c on c.id = r.committer;
 $$;
 
 
 -- Detailed entry for a release
 create type release_entry as
 (
   id                   sha1_git,
   target               sha1_git,
   target_type          object_type,
   date                 timestamptz,
   date_offset          smallint,
   date_neg_utc_offset  boolean,
   name                 bytea,
   comment              bytea,
   synthetic            boolean,
   author_id            bigint,
   author_fullname      bytea,
   author_name          bytea,
   author_email         bytea,
   object_id            bigint
 );
 
 -- Create entries in person from tmp_revision
 create or replace function swh_person_add_from_revision()
     returns void
     language plpgsql
 as $$
 begin
     with t as (
         select author_fullname as fullname, author_name as name, author_email as email from tmp_revision
     union
         select committer_fullname as fullname, committer_name as name, committer_email as email from tmp_revision
     ) insert into person (fullname, name, email)
     select distinct on (fullname) fullname, name, email from t
     where not exists (
         select 1
         from person p
         where t.fullname = p.fullname
     );
     return;
 end
 $$;
 
 
 -- Create entries in revision from tmp_revision
 create or replace function swh_revision_add()
     returns void
     language plpgsql
 as $$
 begin
     perform swh_person_add_from_revision();
 
     insert into revision (id, date, date_offset, date_neg_utc_offset, committer_date, committer_date_offset, committer_date_neg_utc_offset, type, directory, message, author, committer, metadata, synthetic)
     select t.id, t.date, t.date_offset, t.date_neg_utc_offset, t.committer_date, t.committer_date_offset, t.committer_date_neg_utc_offset, t.type, t.directory, t.message, a.id, c.id, t.metadata, t.synthetic
     from tmp_revision t
     left join person a on a.fullname = t.author_fullname
     left join person c on c.fullname = t.committer_fullname;
     return;
 end
 $$;
 
 
 -- Create entries in person from tmp_release
 create or replace function swh_person_add_from_release()
     returns void
     language plpgsql
 as $$
 begin
     with t as (
         select distinct author_fullname as fullname, author_name as name, author_email as email from tmp_release
         where author_fullname is not null
     ) insert into person (fullname, name, email)
     select distinct on (fullname) fullname, name, email from t
     where not exists (
         select 1
         from person p
         where t.fullname = p.fullname
     );
     return;
 end
 $$;
 
 
 -- Create entries in release from tmp_release
 create or replace function swh_release_add()
     returns void
     language plpgsql
 as $$
 begin
     perform swh_person_add_from_release();
 
     insert into release (id, target, target_type, date, date_offset, date_neg_utc_offset, name, comment, author, synthetic)
     select t.id, t.target, t.target_type, t.date, t.date_offset, t.date_neg_utc_offset, t.name, t.comment, a.id, t.synthetic
     from tmp_release t
     left join person a on a.fullname = t.author_fullname;
     return;
 end
 $$;
 
 
 -- add a new origin_visit for origin origin_id at date.
 --
 -- Returns the new visit id.
 create or replace function swh_origin_visit_add(origin_url text, date timestamptz, type text)
     returns bigint
     language sql
 as $$
   with origin_id as (
     select id
     from origin
     where url = origin_url
   ), last_known_visit as (
     select coalesce(max(visit), 0) as visit
     from origin_visit
     where origin = (select id from origin_id)
   )
   insert into origin_visit (origin, date, type, visit, status)
   values ((select id from origin_id), date, type,
           (select visit from last_known_visit) + 1, 'ongoing')
   returning visit;
 $$;
 
 create or replace function swh_snapshot_add(snapshot_id sha1_git)
   returns void
   language plpgsql
 as $$
 declare
   snapshot_object_id snapshot.object_id%type;
 begin
   select object_id from snapshot where id = snapshot_id into snapshot_object_id;
   if snapshot_object_id is null then
      insert into snapshot (id) values (snapshot_id) returning object_id into snapshot_object_id;
      insert into snapshot_branch (name, target_type, target)
        select name, target_type, target from tmp_snapshot_branch tmp
        where not exists (
          select 1
          from snapshot_branch sb
          where sb.name = tmp.name
            and sb.target = tmp.target
            and sb.target_type = tmp.target_type
        )
        on conflict do nothing;
      insert into snapshot_branches (snapshot_id, branch_id)
      select snapshot_object_id, sb.object_id as branch_id
        from tmp_snapshot_branch tmp
        join snapshot_branch sb
        using (name, target, target_type)
        where tmp.target is not null and tmp.target_type is not null
      union
      select snapshot_object_id, sb.object_id as branch_id
        from tmp_snapshot_branch tmp
        join snapshot_branch sb
        using (name)
        where tmp.target is null and tmp.target_type is null
          and sb.target is null and sb.target_type is null;
   end if;
   truncate table tmp_snapshot_branch;
 end;
 $$;
 
 create type snapshot_result as (
   snapshot_id  sha1_git,
   name         bytea,
   target       bytea,
   target_type  snapshot_target
 );
 
 create or replace function swh_snapshot_get_by_id(id sha1_git,
     branches_from bytea default '', branches_count bigint default null,
     target_types snapshot_target[] default NULL)
   returns setof snapshot_result
   language sql
   stable
 as $$
   select
     swh_snapshot_get_by_id.id as snapshot_id, name, target, target_type
   from snapshot_branches
   inner join snapshot_branch on snapshot_branches.branch_id = snapshot_branch.object_id
   where snapshot_id = (select object_id from snapshot where snapshot.id = swh_snapshot_get_by_id.id)
     and (target_types is null or target_type = any(target_types))
     and name >= branches_from
   order by name limit branches_count
 $$;
 
 create type snapshot_size as (
   target_type snapshot_target,
   count bigint
 );
 
 create or replace function swh_snapshot_count_branches(id sha1_git)
   returns setof snapshot_size
   language sql
   stable
 as $$
   SELECT target_type, count(name)
   from swh_snapshot_get_by_id(swh_snapshot_count_branches.id)
   group by target_type;
 $$;
 
 -- Absolute path: directory reference + complete path relative to it
 create type content_dir as (
     directory  sha1_git,
     path       unix_path
 );
 
 
 -- Find the containing directory of a given content, specified by sha1
 -- (note: *not* sha1_git).
 --
 -- Return a pair (dir_it, path) where path is a UNIX path that, from the
 -- directory root, reach down to a file with the desired content. Return NULL
 -- if no match is found.
 --
 -- In case of multiple paths (i.e., pretty much always), an arbitrary one is
 -- chosen.
 create or replace function swh_content_find_directory(content_id sha1)
     returns content_dir
     language sql
     stable
 as $$
     with recursive path as (
 	-- Recursively build a path from the requested content to a root
 	-- directory. Each iteration returns a pair (dir_id, filename) where
 	-- filename is relative to dir_id. Stops when no parent directory can
 	-- be found.
 	(select dir.id as dir_id, dir_entry_f.name as name, 0 as depth
 	 from directory_entry_file as dir_entry_f
 	 join content on content.sha1_git = dir_entry_f.target
 	 join directory as dir on dir.file_entries @> array[dir_entry_f.id]
 	 where content.sha1 = content_id
 	 limit 1)
 	union all
 	(select dir.id as dir_id,
 		(dir_entry_d.name || '/' || path.name)::unix_path as name,
 		path.depth + 1
 	 from path
 	 join directory_entry_dir as dir_entry_d on dir_entry_d.target = path.dir_id
 	 join directory as dir on dir.dir_entries @> array[dir_entry_d.id]
 	 limit 1)
     )
     select dir_id, name from path order by depth desc limit 1;
 $$;
 
 -- Find the visit of origin closest to date visit_date
 -- Breaks ties by selecting the largest visit id
 create or replace function swh_visit_find_by_date(origin_url text, visit_date timestamptz default NOW())
     returns setof origin_visit
     language plpgsql
     stable
 as $$
 declare
   origin_id bigint;
 begin
   select id into origin_id from origin where url=origin_url;
   return query
   with closest_two_visits as ((
     select ov, (date - visit_date), visit as interval
     from origin_visit ov
     where ov.origin = origin_id
           and ov.date >= visit_date
     order by ov.date asc, ov.visit desc
     limit 1
   ) union (
     select ov, (visit_date - date), visit as interval
     from origin_visit ov
     where ov.origin = origin_id
           and ov.date < visit_date
     order by ov.date desc, ov.visit desc
     limit 1
   )) select (ov).* from closest_two_visits order by interval, visit limit 1;
 end
 $$;
 
 -- Object listing by object_id
 
 create or replace function swh_content_list_by_object_id(
     min_excl bigint,
     max_incl bigint
 )
     returns setof content
     language sql
     stable
 as $$
     select * from content
     where object_id > min_excl and object_id <= max_incl
     order by object_id;
 $$;
 
 create or replace function swh_revision_list_by_object_id(
     min_excl bigint,
     max_incl bigint
 )
     returns setof revision_entry
     language sql
     stable
 as $$
     with revs as (
         select * from revision
         where object_id > min_excl and object_id <= max_incl
     )
     select r.id, r.date, r.date_offset, r.date_neg_utc_offset,
            r.committer_date, r.committer_date_offset, r.committer_date_neg_utc_offset,
            r.type, r.directory, r.message,
            a.id, a.fullname, a.name, a.email, c.id, c.fullname, c.name, c.email, r.metadata, r.synthetic,
            array(select rh.parent_id::bytea from revision_history rh where rh.id = r.id order by rh.parent_rank)
                as parents, r.object_id
     from revs r
     left join person a on a.id = r.author
     left join person c on c.id = r.committer
     order by r.object_id;
 $$;
 
 create or replace function swh_release_list_by_object_id(
     min_excl bigint,
     max_incl bigint
 )
     returns setof release_entry
     language sql
     stable
 as $$
     with rels as (
         select * from release
         where object_id > min_excl and object_id <= max_incl
     )
     select r.id, r.target, r.target_type, r.date, r.date_offset, r.date_neg_utc_offset, r.name, r.comment,
            r.synthetic, p.id as author_id, p.fullname as author_fullname, p.name as author_name, p.email as author_email, r.object_id
     from rels r
     left join person p on p.id = r.author
     order by r.object_id;
 $$;
 
 
 -- end revision_metadata functions
 -- origin_metadata functions
 create type origin_metadata_signature as (
     id bigint,
     origin_url text,
     discovery_date timestamptz,
     tool_id bigint,
     metadata jsonb,
     provider_id integer,
     provider_name text,
     provider_type text,
     provider_url  text
 );
 create or replace function swh_origin_metadata_get_by_origin(
        origin text)
     returns setof origin_metadata_signature
     language sql
     stable
 as $$
     select om.id as id, o.url as origin_url, discovery_date, tool_id, om.metadata,
            mp.id as provider_id, provider_name, provider_type, provider_url
     from origin_metadata as om
     inner join metadata_provider mp on om.provider_id = mp.id
     inner join origin o on om.origin_id = o.id
     where o.url = origin
     order by discovery_date desc;
 $$;
 
 create or replace function swh_origin_metadata_get_by_provider_type(
        origin_url text,
        provider_type text)
     returns setof origin_metadata_signature
     language sql
     stable
 as $$
     select om.id as id, o.url as origin_url, discovery_date, tool_id, om.metadata,
            mp.id as provider_id, provider_name, provider_type, provider_url
     from origin_metadata as om
     inner join metadata_provider mp on om.provider_id = mp.id
     inner join origin o on om.origin_id = o.id
     where o.url = origin_url
     and mp.provider_type = provider_type
     order by discovery_date desc;
 $$;
 -- end origin_metadata functions
 
 -- add tmp_tool entries to tool,
 -- skipping duplicates if any.
 --
 -- operates in bulk: 0. create temporary tmp_tool, 1. COPY to
 -- it, 2. call this function to insert and filtering out duplicates
 create or replace function swh_tool_add()
     returns setof tool
     language plpgsql
 as $$
 begin
       insert into tool(name, version, configuration)
       select name, version, configuration from tmp_tool tmp
       on conflict(name, version, configuration) do nothing;
 
       return query
           select id, name, version, configuration
           from tmp_tool join tool
               using(name, version, configuration);
 
       return;
 end
 $$;
 
 
 -- simple counter mapping a textual label to an integer value
 create type counter as (
     label  text,
     value  bigint
 );
 
 -- return statistics about the number of tuples in various SWH tables
 --
 -- Note: the returned values are based on postgres internal statistics
 -- (pg_class table), which are only updated daily (by autovacuum) or so
 create or replace function swh_stat_counters()
     returns setof counter
     language sql
     stable
 as $$
     select object_type as label, value as value
     from object_counts
     where object_type in (
         'content',
         'directory',
         'directory_entry_dir',
         'directory_entry_file',
         'directory_entry_rev',
         'origin',
         'origin_visit',
         'person',
         'release',
         'revision',
         'revision_history',
         'skipped_content',
         'snapshot'
     );
 $$;
 
 create or replace function swh_update_counter(object_type text)
     returns void
     language plpgsql
 as $$
 begin
     execute format('
 	insert into object_counts
     (value, last_update, object_type)
   values
     ((select count(*) from %1$I), NOW(), %1$L)
   on conflict (object_type) do update set
     value = excluded.value,
     last_update = excluded.last_update',
   object_type);
     return;
 end;
 $$;
 
 create or replace function swh_update_counter_bucketed()
     returns void
     language plpgsql
 as $$
 declare
   query text;
   line_to_update int;
   new_value bigint;
 begin
   select
     object_counts_bucketed.line,
     format(
       'select count(%I) from %I where %s',
       coalesce(identifier, '*'),
       object_type,
       coalesce(
         concat_ws(
           ' and ',
           case when bucket_start is not null then
             format('%I >= %L', identifier, bucket_start) -- lower bound condition, inclusive
           end,
           case when bucket_end is not null then
             format('%I < %L', identifier, bucket_end) -- upper bound condition, exclusive
           end
         ),
         'true'
       )
     )
     from object_counts_bucketed
     order by coalesce(last_update, now() - '1 month'::interval) asc
     limit 1
     into line_to_update, query;
 
   execute query into new_value;
 
   update object_counts_bucketed
     set value = new_value,
         last_update = now()
     where object_counts_bucketed.line = line_to_update;
 
 END
 $$;
 
 create or replace function swh_update_counters_from_buckets()
   returns trigger
   language plpgsql
 as $$
 begin
 with to_update as (
   select object_type, sum(value) as value, max(last_update) as last_update
   from object_counts_bucketed ob1
   where not exists (
     select 1 from object_counts_bucketed ob2
     where ob1.object_type = ob2.object_type
     and value is null
     )
   group by object_type
 ) update object_counts
   set
     value = to_update.value,
     last_update = to_update.last_update
   from to_update
   where
     object_counts.object_type = to_update.object_type
     and object_counts.value != to_update.value;
 return null;
 end
 $$;
 
 create trigger update_counts_from_bucketed
   after insert or update
   on object_counts_bucketed
   for each row
   when (NEW.line % 256 = 0)
   execute procedure swh_update_counters_from_buckets();
diff --git a/swh/storage/tests/conftest.py b/swh/storage/tests/conftest.py
index 94986c8..49b979e 100644
--- a/swh/storage/tests/conftest.py
+++ b/swh/storage/tests/conftest.py
@@ -1,267 +1,267 @@
 # Copyright (C) 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 glob
 import pytest
 
 from typing import Union
 
 from pytest_postgresql import factories
 from pytest_postgresql.janitor import DatabaseJanitor, psycopg2, Version
 
 from os import path, environ
 from hypothesis import settings
 from typing import Dict
 
 import swh.storage
 
 from swh.core.utils import numfile_sortkey as sortkey
 
 from swh.model.tests.generate_testdata import gen_contents, gen_origins
 
 
 SQL_DIR = path.join(path.dirname(swh.storage.__file__), 'sql')
 
 environ['LC_ALL'] = 'C.UTF-8'
 
 DUMP_FILES = path.join(SQL_DIR, '*.sql')
 
 # define tests profile. Full documentation is at:
 # https://hypothesis.readthedocs.io/en/latest/settings.html#settings-profiles
 settings.register_profile("fast", max_examples=5, deadline=5000)
 settings.register_profile("slow", max_examples=20, deadline=5000)
 
 
 @pytest.fixture
 def swh_storage(postgresql_proc, swh_storage_postgresql):
     storage_config = {
         'cls': 'local',
         'args': {
             'db': 'postgresql://{user}@{host}:{port}/{dbname}'.format(
                 host=postgresql_proc.host,
                 port=postgresql_proc.port,
                 user='postgres',
                 dbname='tests'),
             'objstorage': {
                 'cls': 'memory',
                 'args': {}
             },
             'journal_writer': {
                 'cls': 'memory',
             },
         },
     }
     storage = swh.storage.get_storage(**storage_config)
     return storage
 
 
 @pytest.fixture
 def swh_contents(swh_storage):
     contents = gen_contents(n=20)
     swh_storage.content_add(contents)
     return contents
 
 
 @pytest.fixture
 def swh_origins(swh_storage):
     origins = gen_origins(n=100)
     swh_storage.origin_add(origins)
     return origins
 
 
 # the postgres_fact factory fixture below is mostly a copy of the code
 # from pytest-postgresql. We need a custom version here to be able to
 # specify our version of the DBJanitor we use.
 def postgresql_fact(process_fixture_name, db_name=None, dump_files=DUMP_FILES):
     @pytest.fixture
     def postgresql_factory(request):
         """
         Fixture factory for PostgreSQL.
 
         :param FixtureRequest request: fixture request object
         :rtype: psycopg2.connection
         :returns: postgresql client
         """
         config = factories.get_config(request)
         if not psycopg2:
             raise ImportError(
                 'No module named psycopg2. Please install it.'
             )
         proc_fixture = request.getfixturevalue(process_fixture_name)
 
         # _, config = try_import('psycopg2', request)
         pg_host = proc_fixture.host
         pg_port = proc_fixture.port
         pg_user = proc_fixture.user
         pg_options = proc_fixture.options
         pg_db = db_name or config['dbname']
         with SwhDatabaseJanitor(
                 pg_user, pg_host, pg_port, pg_db, proc_fixture.version,
                 dump_files=dump_files
         ):
             connection = psycopg2.connect(
                 dbname=pg_db,
                 user=pg_user,
                 host=pg_host,
                 port=pg_port,
                 options=pg_options
             )
             yield connection
             connection.close()
 
     return postgresql_factory
 
 
 swh_storage_postgresql = postgresql_fact('postgresql_proc')
 
 
 # This version of the DatabaseJanitor implement a different setup/teardown
-# behavior than than the stock one: instead of droping, creating and
+# behavior than than the stock one: instead of dropping, creating and
 # initializing the database for each test, it create and initialize the db only
 # once, then it truncate the tables. This is needed to have acceptable test
 # performances.
 class SwhDatabaseJanitor(DatabaseJanitor):
     def __init__(
             self,
             user: str,
             host: str,
             port: str,
             db_name: str,
             version: Union[str, float, Version],
             dump_files: str = DUMP_FILES
     ) -> None:
         super().__init__(user, host, port, db_name, version)
         self.dump_files = sorted(
             glob.glob(dump_files), key=sortkey)
 
     def db_setup(self):
         with psycopg2.connect(
             dbname=self.db_name,
             user=self.user,
             host=self.host,
             port=self.port,
         ) as cnx:
             with cnx.cursor() as cur:
                 for fname in self.dump_files:
                     with open(fname) as fobj:
                         sql = fobj.read().replace('concurrently', '').strip()
                         if sql:
                             cur.execute(sql)
             cnx.commit()
 
     def db_reset(self):
         with psycopg2.connect(
             dbname=self.db_name,
             user=self.user,
             host=self.host,
             port=self.port,
         ) as cnx:
             with cnx.cursor() as cur:
                 cur.execute(
                     "SELECT table_name FROM information_schema.tables "
                     "WHERE table_schema = %s", ('public',))
                 tables = set(table for (table,) in cur.fetchall())
                 for table in tables:
                     cur.execute('truncate table %s cascade' % table)
 
                 cur.execute(
                     "SELECT sequence_name FROM information_schema.sequences "
                     "WHERE sequence_schema = %s", ('public',))
                 seqs = set(seq for (seq,) in cur.fetchall())
                 for seq in seqs:
                     cur.execute('ALTER SEQUENCE %s RESTART;' % seq)
             cnx.commit()
 
     def init(self):
         with self.cursor() as cur:
             cur.execute(
                 "SELECT COUNT(1) FROM pg_database WHERE datname=%s;",
                 (self.db_name,))
             db_exists = cur.fetchone()[0] == 1
             if db_exists:
                 cur.execute(
                     'UPDATE pg_database SET datallowconn=true '
                     'WHERE datname = %s;',
                     (self.db_name,))
 
         if db_exists:
             self.db_reset()
         else:
             with self.cursor() as cur:
                 cur.execute('CREATE DATABASE "{}";'.format(self.db_name))
             self.db_setup()
 
     def drop(self):
         pid_column = 'pid'
         with self.cursor() as cur:
             cur.execute(
                 'UPDATE pg_database SET datallowconn=false '
                 'WHERE datname = %s;', (self.db_name,))
             cur.execute(
                 'SELECT pg_terminate_backend(pg_stat_activity.{})'
                 'FROM pg_stat_activity '
                 'WHERE pg_stat_activity.datname = %s;'.format(pid_column),
                 (self.db_name,))
 
 
 @pytest.fixture
 def sample_data() -> Dict:
     """Pre-defined sample storage object data to manipulate
 
     Returns:
         Dict of data (keys: content, directory, revision, person)
 
     """
     sample_content = {
         'blake2s256': b'\xbf?\x05\xed\xc1U\xd2\xc5\x168Xm\x93\xde}f(HO@\xd0\xacn\x04\x1e\x9a\xb9\xfa\xbf\xcc\x08\xc7',  # noqa
         'sha1': b'g\x15y+\xcb][\\\n\xf28\xb2\x0c_P[\xc8\x89Hk',
         'sha1_git': b'\xf2\xae\xfa\xba\xfa\xa6B\x9b^\xf9Z\xf5\x14\x0cna\xb0\xef\x8b',  # noqa
         'sha256': b"\x87\x022\xedZN\x84\xe8za\xf8'(oA\xc9k\xb1\x80c\x80\xe7J\x06\xea\xd2\xd5\xbeB\x19\xb8\xce",  # noqa
         'length': 48,
         'data': b'temp file for testing content storage conversion',
         'status': 'visible',
     }
 
     sample_content2 = {
         'blake2s256': b'\xbf?\x05\xed\xc1U\xd2\xc5\x168Xm\x93\xde}f(HO@\xd0\xacn\x04\x1e\x9a\xb9\xfa\xbf\xcc\x08\xc7',  # noqa
         'sha1': b'f\x15y+\xcb][\\\n\xf28\xb2\x0c_P[\xc8\x89Hk',
         'sha1_git': b'\xc2\xae\xfa\xba\xfa\xa6B\x9b^\xf9Z\xf5\x14\x0cna\xb0\xef\x8b',  # noqa
         'sha256': b"\x77\x022\xedZN\x84\xe8za\xf8'(oA\xc9k\xb1\x80c\x80\xe7J\x06\xea\xd2\xd5\xbeB\x19\xb8\xce",  # noqa
         'length': 50,
         'data': b'temp file for testing content storage conversion 2',
         'status': 'visible',
     }
 
     sample_directory = {
         'id': b'f\x15y+\xcb][\\\n\xf28\xb2\x0c_P[\xc8\x89Hk',
         'entries': []
     }
 
     sample_person = {
         'name': b'John Doe',
         'email': b'john.doe@institute.org',
         'fullname': b'John Doe <john.doe@institute.org>'
     }
 
     sample_revision = {
         'id': b'f\x15y+\xcb][\\\n\xf28\xb2\x0c_P[\xc8\x89Hk',
         'message': b'something',
         'author': sample_person,
         'committer': sample_person,
         'date': 1567591673,
         'committer_date': 1567591673,
         'type': 'tar',
         'directory': b'\xc2\xae\xfa\xba\xfa\xa6B\x9b^\xf9Z\xf5\x14\x0cna\xb0\xef\x8b',  # noqa
         'synthetic': False,
         'metadata': {},
         'parents': [],
     }
 
     return {
         'content': [sample_content, sample_content2],
         'person': [sample_person],
         'directory': [sample_directory],
         'revision': [sample_revision],
     }