Replace some calls to cursor_to_dict

cursor_to_dict can be surprisinglh expensive for large result sets, so lets
only call it when we need to.

1 files changed, 9 insertions, 34 deletions

diff --git a/synapse/storage/roommember.py b/synapse/storage/roommember.py
index e38d8927bf..23127d3a95 100644
--- a/synapse/storage/roommember.py
+++ b/synapse/storage/roommember.py
@@ -132,14 +132,17 @@ class RoomMemberStore(SQLBaseStore):
     @cached(max_entries=500000, iterable=True)
     def get_users_in_room(self, room_id):
         def f(txn):
-
-            rows = self._get_members_rows_txn(
-                txn,
-                room_id=room_id,
-                membership=Membership.JOIN,
+            sql = (
+                "SELECT m.user_id FROM room_memberships as m"
+                " INNER JOIN current_state_events as c"
+                " ON m.event_id = c.event_id "
+                " AND m.room_id = c.room_id "
+                " AND m.user_id = c.state_key"
+                " WHERE c.type = 'm.room.member' AND c.room_id = ? AND m.membership = ?"
             )
 
-            return [r["user_id"] for r in rows]
+            txn.execute(sql, (room_id, Membership.JOIN,))
+            return [r[0] for r in txn]
         return self.runInteraction("get_users_in_room", f)
 
     @cached()
@@ -246,34 +249,6 @@ class RoomMemberStore(SQLBaseStore):
 
         return results
 
-    def _get_members_rows_txn(self, txn, room_id, membership=None, user_id=None):
-        where_clause = "c.room_id = ?"
-        where_values = [room_id]
-
-        if membership:
-            where_clause += " AND m.membership = ?"
-            where_values.append(membership)
-
-        if user_id:
-            where_clause += " AND m.user_id = ?"
-            where_values.append(user_id)
-
-        sql = (
-            "SELECT m.* FROM room_memberships as m"
-            " INNER JOIN current_state_events as c"
-            " ON m.event_id = c.event_id "
-            " AND m.room_id = c.room_id "
-            " AND m.user_id = c.state_key"
-            " WHERE c.type = 'm.room.member' AND %(where)s"
-        ) % {
-            "where": where_clause,
-        }
-
-        txn.execute(sql, where_values)
-        rows = self.cursor_to_dict(txn)
-
-        return rows
-
     @cachedInlineCallbacks(max_entries=500000, iterable=True)
     def get_rooms_for_user(self, user_id):
         """Returns a set of room_ids the user is currently joined to