diff options
| -rw-r--r-- | changelog.d/8396.feature | 1 | ||||
| -rw-r--r-- | synapse/storage/databases/main/schema/delta/58/14events_instance_name.sql.postgres | 4 | ||||
| -rw-r--r-- | synapse/storage/util/id_generators.py | 6 |
3 files changed, 9 insertions, 2 deletions
diff --git a/changelog.d/8396.feature b/changelog.d/8396.feature new file mode 100644 index 0000000000..b363e929ea --- /dev/null +++ b/changelog.d/8396.feature @@ -0,0 +1 @@ +Add experimental support for sharding event persister. diff --git a/synapse/storage/databases/main/schema/delta/58/14events_instance_name.sql.postgres b/synapse/storage/databases/main/schema/delta/58/14events_instance_name.sql.postgres index 97c1e6a0c5..c31f9af82a 100644 --- a/synapse/storage/databases/main/schema/delta/58/14events_instance_name.sql.postgres +++ b/synapse/storage/databases/main/schema/delta/58/14events_instance_name.sql.postgres @@ -21,6 +21,8 @@ SELECT setval('events_stream_seq', ( CREATE SEQUENCE IF NOT EXISTS events_backfill_stream_seq; +-- If the server has never backfilled a room then doing `-MIN(...)` will give +-- a negative result, hence why we do `GREATEST(...)` SELECT setval('events_backfill_stream_seq', ( - SELECT COALESCE(-MIN(stream_ordering), 1) FROM events + SELECT GREATEST(COALESCE(-MIN(stream_ordering), 1), 1) FROM events )); diff --git a/synapse/storage/util/id_generators.py b/synapse/storage/util/id_generators.py index 727fcc521c..4269eaf918 100644 --- a/synapse/storage/util/id_generators.py +++ b/synapse/storage/util/id_generators.py @@ -287,8 +287,12 @@ class MultiWriterIdGenerator: min_stream_id = min(self._current_positions.values(), default=None) if min_stream_id is None: + # We add a GREATEST here to ensure that the result is always + # positive. (This can be a problem for e.g. backfill streams where + # the server has never backfilled). sql = """ - SELECT COALESCE(%(agg)s(%(id)s), 1) FROM %(table)s + SELECT GREATEST(COALESCE(%(agg)s(%(id)s), 1), 1) + FROM %(table)s """ % { "id": id_column, "table": table, |