Merge pull request #5792 from matrix-org/erikj/fix_bg_update

Fix current_state_events membership background update.

3 files changed, 2 insertions, 1 deletions

diff --git a/changelog.d/5792.misc b/changelog.d/5792.misc
new file mode 100644

index 0000000000..5e15dfd5fa
--- /dev/null
+++ b/changelog.d/5792.misc
@@ -0,0 +1 @@
+Reduce database IO usage by optimising queries for current membership.
diff --git a/synapse/storage/roommember.py b/synapse/storage/roommember.py

index e60409ed73..eecb276465 100644
--- a/synapse/storage/roommember.py
+++ b/synapse/storage/roommember.py
@@ -935,7 +935,7 @@ class RoomMemberStore(RoomMemberWorkerStore):
             while processed < batch_size:
                 txn.execute(
                     """
-                        SELECT MIN(room_id) FROM rooms WHERE room_id > ?
+                        SELECT MIN(room_id) FROM current_state_events WHERE room_id > ?
                     """,
                     (last_processed_room,),
                 )
diff --git a/synapse/storage/schema/delta/56/current_state_events_membership.sql b/synapse/storage/schema/delta/56/current_state_events_membership_mk2.sql

index b2e08cd85d..b2e08cd85d 100644
--- a/synapse/storage/schema/delta/56/current_state_events_membership.sql
+++ b/synapse/storage/schema/delta/56/current_state_events_membership_mk2.sql