From ac27f6a35ebb63d502769edec642fbf70a178a60 Mon Sep 17 00:00:00 2001 From: Richard van der Hoff Date: Wed, 14 Feb 2018 16:41:12 +0000 Subject: purge_history: handle sqlite asshattery apparently creating a temporary table commits the transaction. because that's a useful thing. --- synapse/storage/events.py | 46 +++++++++++++++++++++++++++------------------- 1 file changed, 27 insertions(+), 19 deletions(-) diff --git a/synapse/storage/events.py b/synapse/storage/events.py index c81bc75eae..90e910f615 100644 --- a/synapse/storage/events.py +++ b/synapse/storage/events.py @@ -2093,6 +2093,27 @@ class EventsStore(SQLBaseStore): # state_groups # state_groups_state + # we will build a temporary table listing the events so that we don't + # have to keep shovelling the list back and forth across the + # connection. Annoyingly the python sqlite driver commits the + # transaction on CREATE, so let's do this first. + # + # furthermore, we might already have the table from a previous (failed) + # purge attempt, so let's drop the table first. + + txn.execute("DROP TABLE IF EXISTS events_to_purge") + + txn.execute( + "CREATE TEMPORARY TABLE events_to_purge (" + " event_id TEXT NOT NULL," + " should_delete BOOLEAN NOT NULL" + ")" + ) + + # 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)") + # First ensure that we're not about to delete all the forward extremeties txn.execute( "SELECT e.event_id, e.depth FROM events as e " @@ -2115,20 +2136,6 @@ 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( - "CREATE TEMPORARY TABLE events_to_purge (" - " event_id TEXT NOT NULL," - " should_delete BOOLEAN NOT NULL" - ")" - ) - - # 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: @@ -2339,11 +2346,6 @@ class EventsStore(SQLBaseStore): (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 # persists events (because upsert), and once we run this update, we # will block that for the rest of our transaction. @@ -2356,6 +2358,12 @@ class EventsStore(SQLBaseStore): (topological_ordering, room_id,) ) + # finally, drop the temp table. this will commit the txn in sqlite, + # so make sure to keep this actually last. + txn.execute( + "DROP TABLE events_to_purge" + ) + logger.info("[purge] done") @defer.inlineCallbacks -- cgit 1.4.1