Merge remote-tracking branch 'origin/release-v1.38' into matrix-org-hotfixes

2 files changed, 23 insertions, 2 deletions

diff --git a/synapse/storage/databases/main/events_bg_updates.py b/synapse/storage/databases/main/events_bg_updates.py

index 1c95c66648..29f33bac55 100644
--- a/synapse/storage/databases/main/events_bg_updates.py
+++ b/synapse/storage/databases/main/events_bg_updates.py
@@ -1146,6 +1146,16 @@ class EventsBackgroundUpdatesStore(SQLBaseStore):
                 logger.info("completing stream_ordering migration: %s", sql)
                 txn.execute(sql)
 
+        # ANALYZE the new column to build stats on it, to encourage PostgreSQL to use the
+        # indexes on it.
+        # We need to pass execute a dummy function to handle the txn's result otherwise
+        # it tries to call fetchall() on it and fails because there's no result to fetch.
+        await self.db_pool.execute(
+            "background_analyze_new_stream_ordering_column",
+            lambda txn: None,
+            "ANALYZE events(stream_ordering2)",
+        )
+
         await self.db_pool.runInteraction(
             "_background_replace_stream_ordering_column", process
         )
diff --git a/synapse/storage/databases/main/lock.py b/synapse/storage/databases/main/lock.py

index e76188328c..774861074c 100644
--- a/synapse/storage/databases/main/lock.py
+++ b/synapse/storage/databases/main/lock.py
@@ -310,14 +310,25 @@ class Lock:
         _excinst: Optional[BaseException],
         _exctb: Optional[TracebackType],
     ) -> bool:
+        await self.release()
+
+        return False
+
+    async def release(self) -> None:
+        """Release the lock.
+
+        This is automatically called when using the lock as a context manager.
+        """
+
+        if self._dropped:
+            return
+
         if self._looping_call.running:
             self._looping_call.stop()
 
         await self._store._drop_lock(self._lock_name, self._lock_key, self._token)
         self._dropped = True
 
-        return False
-
     def __del__(self) -> None:
         if not self._dropped:
             # We should not be dropped without the lock being released (unless