From 5fcbf1e07c5f7c2ce0ec44c2569116507caa0183 Mon Sep 17 00:00:00 2001 From: Richard van der Hoff Date: Wed, 14 Feb 2018 11:02:22 +0000 Subject: Rework event purge to use a temporary table ... which should speed things up by reducing the amount of data being shuffled across the connection --- synapse/storage/events.py | 93 +++++++++++++++++++++++++++++------------------ 1 file changed, 58 insertions(+), 35 deletions(-) diff --git a/synapse/storage/events.py b/synapse/storage/events.py index bbb6aa992c..5a2e6a03d5 100644 --- a/synapse/storage/events.py +++ b/synapse/storage/events.py @@ -2115,23 +2115,44 @@ class EventsStore(SQLBaseStore): logger.info("[purge] looking for events to delete") + # we build a temporary table listing the events so that we don't have + # to keep shovelling the list back and forth across the connection. + txn.execute( - "SELECT event_id, state_key FROM events" - " LEFT JOIN state_events USING (room_id, event_id)" - " WHERE room_id = ? AND topological_ordering < ?", - (room_id, topological_ordering,) + "CREATE TEMPORARY TABLE events_to_purge (" + " event_id TEXT NOT NULL," + " should_delete BOOLEAN NOT NULL" + ")" ) - event_rows = txn.fetchall() - to_delete = [ - (event_id,) for event_id, state_key in event_rows - if state_key is None and ( - delete_local_events or not self.hs.is_mine_id(event_id) - ) - ] + # create an index on should_delete because later we'll be looking for + # the should_delete / shouldn't_delete subsets + txn.execute("CREATE INDEX ON events_to_purge(should_delete)") + + should_delete_expr = "state_key IS NULL" + should_delete_params = () + if not delete_local_events: + should_delete_expr += " AND event_id NOT LIKE ?" + should_delete_params += ("%:" + self.hs.hostname, ) + + should_delete_params += (room_id, topological_ordering) + + txn.execute( + "INSERT INTO events_to_purge" + " SELECT event_id, %s" + " FROM events AS e LEFT JOIN state_events USING (event_id)" + " WHERE e.room_id = ? AND topological_ordering < ?" % ( + should_delete_expr, + ), + should_delete_params, + ) + txn.execute( + "SELECT event_id, should_delete FROM events_to_purge" + ) + event_rows = txn.fetchall() logger.info( "[purge] found %i events before cutoff, of which %i can be deleted", - len(event_rows), len(to_delete), + len(event_rows), sum(1 for e in event_rows if e[1]), ) logger.info("[purge] Finding new backward extremities") @@ -2139,12 +2160,11 @@ class EventsStore(SQLBaseStore): # We calculate the new entries for the backward extremeties by finding # all events that point to events that are to be purged txn.execute( - "SELECT DISTINCT e.event_id FROM events as e" - " INNER JOIN event_edges as ed ON e.event_id = ed.prev_event_id" - " INNER JOIN events as e2 ON e2.event_id = ed.event_id" - " WHERE e.room_id = ? AND e.topological_ordering < ?" - " AND e2.topological_ordering >= ?", - (room_id, topological_ordering, topological_ordering) + "SELECT DISTINCT e.event_id FROM events_to_purge AS e" + " INNER JOIN event_edges AS ed ON e.event_id = ed.prev_event_id" + " INNER JOIN events AS e2 ON e2.event_id = ed.event_id" + " WHERE e2.topological_ordering >= ?", + (topological_ordering, ) ) new_backwards_extrems = txn.fetchall() @@ -2172,12 +2192,11 @@ class EventsStore(SQLBaseStore): "SELECT state_group FROM event_to_state_groups" " INNER JOIN events USING (event_id)" " WHERE state_group IN (" - " SELECT DISTINCT state_group FROM events" + " SELECT DISTINCT state_group FROM events_to_purge" " INNER JOIN event_to_state_groups USING (event_id)" - " WHERE room_id = ? AND topological_ordering < ?" " )" " GROUP BY state_group HAVING MAX(topological_ordering) < ?", - (room_id, topological_ordering, topological_ordering) + (topological_ordering, ) ) state_rows = txn.fetchall() @@ -2262,9 +2281,9 @@ class EventsStore(SQLBaseStore): ) logger.info("[purge] removing events from event_to_state_groups") - txn.executemany( - "DELETE FROM event_to_state_groups WHERE event_id = ?", - [(event_id,) for event_id, _ in event_rows] + txn.execute( + "DELETE FROM event_to_state_groups " + "WHERE event_id IN (SELECT event_id from events_to_purge)" ) for event_id, _ in event_rows: txn.call_after(self._get_state_group_for_event.invalidate, ( @@ -2289,22 +2308,26 @@ class EventsStore(SQLBaseStore): ): logger.info("[purge] removing events from %s", table) - txn.executemany( - "DELETE FROM %s WHERE event_id = ?" % (table,), - to_delete + txn.execute( + "DELETE FROM %s WHERE event_id IN (" + " SELECT event_id FROM events_to_purge WHERE should_delete" + ")" % (table,), ) # Mark all state and own events as outliers logger.info("[purge] marking remaining events as outliers") - txn.executemany( + txn.execute( "UPDATE events SET outlier = ?" - " WHERE event_id = ?", - [ - (True, event_id,) for event_id, state_key in event_rows - if state_key is not None or ( - not delete_local_events and self.hs.is_mine_id(event_id) - ) - ] + " WHERE event_id IN (" + " SELECT event_id FROM events_to_purge " + " WHERE NOT should_delete" + ")", + (True,), + ) + + # we're now done with the temporary table + txn.execute( + "DROP TABLE events_to_purge" ) # synapse tries to take out an exclusive lock on room_depth whenever it -- cgit 1.4.1