Add an index to event_search

synapse/storage/background_updates.py

@@ -210,7 +210,9 @@ def register_background_update_handler(self, update_name, update_handler):
         self._background_update_handlers[update_name] = update_handler
 
     def register_background_index_update(self, update_name, index_name,
-                                         table, columns, where_clause=None):
+                                         table, columns, where_clause=None,
+                                         unique=False,
+                                         psql_only=False):
         """Helper for store classes to do a background index addition
 
         To use:
@@ -226,6 +228,9 @@ def register_background_index_update(self, update_name, index_name,
             index_name (str): name of index to add
             table (str): table to add index to
             columns (list[str]): columns/expressions to include in index
+            unique (bool): true to make a UNIQUE index
+            psql_only: true to only create this index on psql databases (useful
+                for virtual sqlite tables)
         """
 
         def create_index_psql(conn):
@@ -245,9 +250,11 @@ def create_index_psql(conn):
                 c.execute(sql)
 
                 sql = (
-                    "CREATE INDEX CONCURRENTLY %(name)s ON %(table)s"
+                    "CREATE %(unique)s INDEX CONCURRENTLY %(name)s"
+                    " ON %(table)s"
                     " (%(columns)s) %(where_clause)s"
                 ) % {
+                    "unique": "UNIQUE" if unique else "",
                     "name": index_name,
                     "table": table,
                     "columns": ", ".join(columns),
@@ -270,9 +277,10 @@ def create_index_sqlite(conn):
             # down at the wrong moment - hance we use IF NOT EXISTS. (SQLite
             # has supported CREATE TABLE|INDEX IF NOT EXISTS since 3.3.0.)
             sql = (
-                "CREATE INDEX IF NOT EXISTS %(name)s ON %(table)s"
+                "CREATE %(unique)s INDEX IF NOT EXISTS %(name)s ON %(table)s"
                 " (%(columns)s)"
             ) % {
+                "unique": "UNIQUE" if unique else "",
                 "name": index_name,
                 "table": table,
                 "columns": ", ".join(columns),
@@ -284,13 +292,16 @@ def create_index_sqlite(conn):
 
         if isinstance(self.database_engine, engines.PostgresEngine):
             runner = create_index_psql
+        elif psql_only:
+            runner = None
         else:
             runner = create_index_sqlite
 
         @defer.inlineCallbacks
         def updater(progress, batch_size):
-            logger.info("Adding index %s to %s", index_name, table)
-            yield self.runWithConnection(runner)
+            if runner is not None:
+                logger.info("Adding index %s to %s", index_name, table)
+                yield self.runWithConnection(runner)
             yield self._end_background_update(update_name)
             defer.returnValue(1)
 

synapse/storage/events.py

@@ -207,6 +207,18 @@ def __init__(self, hs):
             where_clause="contains_url = true AND outlier = false",
         )
 
+        # an event_id index on event_search is useful for the purge_history
+        # api. Plus it means we get to enforce some integrity with a UNIQUE
+        # clause
+        self.register_background_index_update(
+            "event_search_event_id_idx",
+            index_name="event_search_event_id_idx",
+            table="event_search",
+            columns=["event_id"],
+            unique=True,
+            psql_only=True,
+        )
+
         self._event_persist_queue = _EventPeristenceQueue()
 
     def persist_events(self, events_and_contexts, backfilled=False):
@@ -2022,6 +2034,8 @@ def _delete_old_state_txn(self, txn, room_id, topological_ordering):
                 400, "topological_ordering is greater than forward extremeties"
             )
 
+        logger.debug("[purge] looking for events to delete")
+
         txn.execute(
             "SELECT event_id, state_key FROM events"
             " LEFT JOIN state_events USING (room_id, event_id)"
@@ -2030,6 +2044,14 @@ def _delete_old_state_txn(self, txn, room_id, topological_ordering):
         )
         event_rows = txn.fetchall()
 
+        to_delete = [
+            (event_id,) for event_id, state_key in event_rows
+            if state_key is None and not self.hs.is_mine_id(event_id)
+        ]
+        logger.info(
+            "[purge] found %i events before cutoff, of which %i are remote"
+            " non-state events to delete", len(event_rows), len(to_delete))
+
         for event_id, state_key in event_rows:
             txn.call_after(self._get_state_group_for_event.invalidate, (event_id,))
 
@@ -2080,6 +2102,7 @@ def _delete_old_state_txn(self, txn, room_id, topological_ordering):
         )
 
         state_rows = txn.fetchall()
+        logger.debug("[purge] found %i redundant state groups", len(state_rows))
 
         # make a set of the redundant state groups, so that we can look them up
         # efficiently
@@ -2173,10 +2196,6 @@ def _delete_old_state_txn(self, txn, room_id, topological_ordering):
         )
 
         # Delete all remote non-state events
-        to_delete = [
-            (event_id,) for event_id, state_key in event_rows
-            if state_key is None and not self.hs.is_mine_id(event_id)
-        ]
         for table in (
             "events",
             "event_json",
@@ -2192,15 +2211,15 @@ def _delete_old_state_txn(self, txn, room_id, topological_ordering):
             "event_signatures",
             "rejections",
         ):
-            logger.debug("[purge] removing non-state events from %s", table)
+            logger.debug("[purge] removing remote non-state events from %s", table)
 
             txn.executemany(
                 "DELETE FROM %s WHERE event_id = ?" % (table,),
                 to_delete
             )
 
         # Mark all state and own events as outliers
-        logger.debug("[purge] marking events as outliers")
+        logger.debug("[purge] marking remaining events as outliers")
         txn.executemany(
             "UPDATE events SET outlier = ?"
             " WHERE event_id = ?",
@@ -2210,7 +2229,7 @@ def _delete_old_state_txn(self, txn, room_id, topological_ordering):
             ]
         )
 
-        logger.debug("[purge] done")
+        logger.info("[purge] done")
 
     @defer.inlineCallbacks
     def is_event_after(self, event_id1, event_id2):

synapse/storage/schema/delta/37/remove_auth_idx.py

@@ -36,6 +36,10 @@
 -- and is used incredibly rarely.
 DROP INDEX IF EXISTS events_order_topo_stream_room;
 
+-- an equivalent index to this actually gets re-created in delta 41, because it
+-- turned out that deleting it wasn't a great plan :/. In any case, let's
+-- delete it here, and delta 41 will create a new one with an added UNIQUE
+-- constraint
 DROP INDEX IF EXISTS event_search_ev_idx;
 """
 

synapse/storage/schema/delta/41/event_search_event_id_idx.sql

@@ -0,0 +1,17 @@
+/* Copyright 2017 Vector Creations Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+INSERT into background_updates (update_name, progress_json)
+    VALUES ('event_search_event_id_idx', '{}');