From 1d7702833d27f2e87e6598b5de9aad878e716c4b Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Thu, 30 Apr 2015 10:16:12 +0100
Subject: [PATCH] Make simple query rather than long one and then throw away
 half the results

---
 synapse/handlers/message.py |  3 +--
 synapse/storage/room.py     | 10 ++++++++++
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 9667bb8674..22e19af17f 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -267,8 +267,7 @@ class MessageHandler(BaseHandler):
             user, pagination_config.get_source_config("presence"), None
         )
 
-        public_rooms = yield self.store.get_rooms(is_public=True)
-        public_room_ids = [r["room_id"] for r in public_rooms]
+        public_room_ids = yield self.store.get_public_room_ids()
 
         limit = pagin_config.limit
         if limit is None:
diff --git a/synapse/storage/room.py b/synapse/storage/room.py
index 48ebb33057..2e77b9d79b 100644
--- a/synapse/storage/room.py
+++ b/synapse/storage/room.py
@@ -75,6 +75,16 @@ class RoomStore(SQLBaseStore):
             allow_none=True,
         )
 
+    def get_public_room_ids(self):
+        return self._simple_select_onecol(
+            table="rooms",
+            keyvalues={
+                "is_public": True,
+            },
+            retcol="room_id",
+            desc="get_public_room_ids",
+        )
+
     @defer.inlineCallbacks
     def get_rooms(self, is_public):
         """Retrieve a list of all public rooms.