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authorJason Little <realtyem@gmail.com>2023-07-05 05:44:02 -0500
committerGitHub <noreply@github.com>2023-07-05 11:44:02 +0100
commit4cf9f92f395e8c448b94eccb48fbfe2e7e61d7cd (patch)
tree68955518cee50e7032ce1565697a27bd1a2ecddc /synapse/storage
parentAdd foreign key constraint to `event_forward_extremities`. (#15751) (diff)
downloadsynapse-4cf9f92f395e8c448b94eccb48fbfe2e7e61d7cd.tar.xz
Fix could not serialize access due to concurrent `DELETE` from presence_stream (#15826)
* Change update_presence to have a isolation level of READ_COMMITTED

* changelog
Diffstat (limited to 'synapse/storage')
-rw-r--r--synapse/storage/databases/main/presence.py7
1 files changed, 6 insertions, 1 deletions
diff --git a/synapse/storage/databases/main/presence.py b/synapse/storage/databases/main/presence.py
index beb210f8ee..b51d20ac26 100644
--- a/synapse/storage/databases/main/presence.py
+++ b/synapse/storage/databases/main/presence.py
@@ -11,7 +11,6 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-
 from typing import TYPE_CHECKING, Any, Dict, Iterable, List, Optional, Tuple, cast
 
 from synapse.api.presence import PresenceState, UserPresenceState
@@ -24,6 +23,7 @@ from synapse.storage.database import (
 )
 from synapse.storage.databases.main.cache import CacheInvalidationWorkerStore
 from synapse.storage.engines import PostgresEngine
+from synapse.storage.engines._base import IsolationLevel
 from synapse.storage.types import Connection
 from synapse.storage.util.id_generators import (
     AbstractStreamIdGenerator,
@@ -115,11 +115,16 @@ class PresenceStore(PresenceBackgroundUpdateStore, CacheInvalidationWorkerStore)
         )
 
         async with stream_ordering_manager as stream_orderings:
+            # Run the interaction with an isolation level of READ_COMMITTED to avoid
+            # serialization errors(and rollbacks) in the database. This way it will
+            # ignore new rows during the DELETE, but will pick them up the next time
+            # this is run. Currently, that is between 5-60 seconds.
             await self.db_pool.runInteraction(
                 "update_presence",
                 self._update_presence_txn,
                 stream_orderings,
                 presence_states,
+                isolation_level=IsolationLevel.READ_COMMITTED,
             )
 
         return stream_orderings[-1], self._presence_id_gen.get_current_token()