diff --git a/synapse/storage/search.py b/synapse/storage/search.py
index f1ac9ba0fd..2755acff40 100644
--- a/synapse/storage/search.py
+++ b/synapse/storage/search.py
@@ -38,6 +38,7 @@ class SearchStore(BackgroundUpdateStore):
EVENT_SEARCH_UPDATE_NAME = "event_search"
EVENT_SEARCH_ORDER_UPDATE_NAME = "event_search_order"
EVENT_SEARCH_USE_GIST_POSTGRES_NAME = "event_search_postgres_gist"
+ EVENT_SEARCH_USE_GIN_POSTGRES_NAME = "event_search_postgres_gin"
def __init__(self, db_conn, hs):
super(SearchStore, self).__init__(db_conn, hs)
@@ -48,9 +49,19 @@ class SearchStore(BackgroundUpdateStore):
self.EVENT_SEARCH_ORDER_UPDATE_NAME,
self._background_reindex_search_order
)
- self.register_background_update_handler(
+
+ # we used to have a background update to turn the GIN index into a
+ # GIST one; we no longer do that (obviously) because we actually want
+ # a GIN index. However, it's possible that some people might still have
+ # the background update queued, so we register a handler to clear the
+ # background update.
+ self.register_noop_background_update(
self.EVENT_SEARCH_USE_GIST_POSTGRES_NAME,
- self._background_reindex_gist_search
+ )
+
+ self.register_background_update_handler(
+ self.EVENT_SEARCH_USE_GIN_POSTGRES_NAME,
+ self._background_reindex_gin_search
)
@defer.inlineCallbacks
@@ -151,25 +162,48 @@ class SearchStore(BackgroundUpdateStore):
defer.returnValue(result)
@defer.inlineCallbacks
- def _background_reindex_gist_search(self, progress, batch_size):
+ def _background_reindex_gin_search(self, progress, batch_size):
+ """This handles old synapses which used GIST indexes, if any;
+ converting them back to be GIN as per the actual schema.
+ """
+
def create_index(conn):
conn.rollback()
- conn.set_session(autocommit=True)
- c = conn.cursor()
- c.execute(
- "CREATE INDEX CONCURRENTLY event_search_fts_idx_gist"
- " ON event_search USING GIST (vector)"
- )
+ # we have to set autocommit, because postgres refuses to
+ # CREATE INDEX CONCURRENTLY without it.
+ conn.set_session(autocommit=True)
- c.execute("DROP INDEX event_search_fts_idx")
+ try:
+ c = conn.cursor()
- conn.set_session(autocommit=False)
+ # if we skipped the conversion to GIST, we may already/still
+ # have an event_search_fts_idx; unfortunately postgres 9.4
+ # doesn't support CREATE INDEX IF EXISTS so we just catch the
+ # exception and ignore it.
+ import psycopg2
+ try:
+ c.execute(
+ "CREATE INDEX CONCURRENTLY event_search_fts_idx"
+ " ON event_search USING GIN (vector)"
+ )
+ except psycopg2.ProgrammingError as e:
+ logger.warn(
+ "Ignoring error %r when trying to switch from GIST to GIN",
+ e
+ )
+
+ # we should now be able to delete the GIST index.
+ c.execute(
+ "DROP INDEX IF EXISTS event_search_fts_idx_gist"
+ )
+ finally:
+ conn.set_session(autocommit=False)
if isinstance(self.database_engine, PostgresEngine):
yield self.runWithConnection(create_index)
- yield self._end_background_update(self.EVENT_SEARCH_USE_GIST_POSTGRES_NAME)
+ yield self._end_background_update(self.EVENT_SEARCH_USE_GIN_POSTGRES_NAME)
defer.returnValue(1)
@defer.inlineCallbacks
@@ -289,7 +323,30 @@ class SearchStore(BackgroundUpdateStore):
entry.stream_ordering, entry.origin_server_ts,
) for entry in entries)
+ # inserts to a GIN index are normally batched up into a pending
+ # list, and then all committed together once the list gets to a
+ # certain size. The trouble with that is that postgres (pre-9.5)
+ # uses work_mem to determine the length of the list, and work_mem
+ # is typically very large.
+ #
+ # We therefore reduce work_mem while we do the insert.
+ #
+ # (postgres 9.5 uses the separate gin_pending_list_limit setting,
+ # so doesn't suffer the same problem, but changing work_mem will
+ # be harmless)
+ #
+ # Note that we don't need to worry about restoring it on
+ # exception, because exceptions will cause the transaction to be
+ # rolled back, including the effects of the SET command.
+ #
+ # Also: we use SET rather than SET LOCAL because there's lots of
+ # other stuff going on in this transaction, which want to have the
+ # normal work_mem setting.
+
+ txn.execute("SET work_mem='256kB'")
txn.executemany(sql, args)
+ txn.execute("RESET work_mem")
+
elif isinstance(self.database_engine, Sqlite3Engine):
sql = (
"INSERT INTO event_search (event_id, room_id, key, value)"
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