From d241a1350d5b0e1cf8262114f0cb34325cb91a26 Mon Sep 17 00:00:00 2001 From: Erik Johnston Date: Fri, 14 Oct 2022 14:46:23 +0100 Subject: [PATCH] Fix background update to use an index (#14181) --- changelog.d/14181.bugfix | 1 + .../databases/main/event_push_actions.py | 62 +++++++++++++++---- 2 files changed, 52 insertions(+), 11 deletions(-) create mode 100644 changelog.d/14181.bugfix diff --git a/changelog.d/14181.bugfix b/changelog.d/14181.bugfix new file mode 100644 index 000000000..36521c670 --- /dev/null +++ b/changelog.d/14181.bugfix @@ -0,0 +1 @@ +Fix poor performance of the `event_push_backfill_thread_id` background update, which was introduced in Synapse 1.68.0rc1. diff --git a/synapse/storage/databases/main/event_push_actions.py b/synapse/storage/databases/main/event_push_actions.py index 7f7bcb709..72cf91eb3 100644 --- a/synapse/storage/databases/main/event_push_actions.py +++ b/synapse/storage/databases/main/event_push_actions.py @@ -269,11 +269,11 @@ class EventPushActionsWorkerStore(ReceiptsWorkerStore, StreamWorkerStore, SQLBas event_push_actions_done = progress.get("event_push_actions_done", False) def add_thread_id_txn( - txn: LoggingTransaction, table_name: str, start_stream_ordering: int + txn: LoggingTransaction, start_stream_ordering: int ) -> int: - sql = f""" + sql = """ SELECT stream_ordering - FROM {table_name} + FROM event_push_actions WHERE thread_id IS NULL AND stream_ordering > ? @@ -285,7 +285,7 @@ class EventPushActionsWorkerStore(ReceiptsWorkerStore, StreamWorkerStore, SQLBas # No more rows to process. rows = txn.fetchall() if not rows: - progress[f"{table_name}_done"] = True + progress["event_push_actions_done"] = True self.db_pool.updates._background_update_progress_txn( txn, "event_push_backfill_thread_id", progress ) @@ -294,8 +294,8 @@ class EventPushActionsWorkerStore(ReceiptsWorkerStore, StreamWorkerStore, SQLBas # Update the thread ID for any of those rows. max_stream_ordering = rows[-1][0] - sql = f""" - UPDATE {table_name} + sql = """ + UPDATE event_push_actions SET thread_id = 'main' WHERE ? < stream_ordering AND stream_ordering <= ? AND thread_id IS NULL """ @@ -309,7 +309,50 @@ class EventPushActionsWorkerStore(ReceiptsWorkerStore, StreamWorkerStore, SQLBas # Update progress. processed_rows = txn.rowcount - progress[f"max_{table_name}_stream_ordering"] = max_stream_ordering + progress["max_event_push_actions_stream_ordering"] = max_stream_ordering + self.db_pool.updates._background_update_progress_txn( + txn, "event_push_backfill_thread_id", progress + ) + + return processed_rows + + def add_thread_id_summary_txn(txn: LoggingTransaction) -> int: + min_user_id = progress.get("max_summary_user_id", "") + min_room_id = progress.get("max_summary_room_id", "") + + # Slightly overcomplicated query for getting the Nth user ID / room + # ID tuple, or the last if there are less than N remaining. + sql = """ + SELECT user_id, room_id FROM ( + SELECT user_id, room_id FROM event_push_summary + WHERE (user_id, room_id) > (?, ?) + AND thread_id IS NULL + ORDER BY user_id, room_id + LIMIT ? + ) AS e + ORDER BY user_id DESC, room_id DESC + LIMIT 1 + """ + + txn.execute(sql, (min_user_id, min_room_id, batch_size)) + row = txn.fetchone() + if not row: + return 0 + + max_user_id, max_room_id = row + + sql = """ + UPDATE event_push_summary + SET thread_id = 'main' + WHERE + (?, ?) < (user_id, room_id) AND (user_id, room_id) <= (?, ?) + AND thread_id IS NULL + """ + txn.execute(sql, (min_user_id, min_room_id, max_user_id, max_room_id)) + processed_rows = txn.rowcount + + progress["max_summary_user_id"] = max_user_id + progress["max_summary_room_id"] = max_room_id self.db_pool.updates._background_update_progress_txn( txn, "event_push_backfill_thread_id", progress ) @@ -325,15 +368,12 @@ class EventPushActionsWorkerStore(ReceiptsWorkerStore, StreamWorkerStore, SQLBas result = await self.db_pool.runInteraction( "event_push_backfill_thread_id", add_thread_id_txn, - "event_push_actions", progress.get("max_event_push_actions_stream_ordering", 0), ) else: result = await self.db_pool.runInteraction( "event_push_backfill_thread_id", - add_thread_id_txn, - "event_push_summary", - progress.get("max_event_push_summary_stream_ordering", 0), + add_thread_id_summary_txn, ) # Only done after the event_push_summary table is done.