1 files changed, 26 insertions, 18 deletions
diff --git a/synapse/storage/stream.py b/synapse/storage/stream.py
index c236dafafb..cf84938be5 100644
--- a/synapse/storage/stream.py
+++ b/synapse/storage/stream.py
@@ -36,7 +36,7 @@ what sort order was used:
 from twisted.internet import defer
 
 from ._base import SQLBaseStore
-from synapse.util.caches.descriptors import cachedInlineCallbacks
+from synapse.util.caches.descriptors import cached
 from synapse.api.constants import EventTypes
 from synapse.types import RoomStreamToken
 from synapse.util.logcontext import preserve_fn
@@ -184,6 +184,9 @@ class StreamStore(SQLBaseStore):
     @defer.inlineCallbacks
     def get_room_events_stream_for_room(self, room_id, from_key, to_key, limit=0,
                                         order='DESC'):
+        # Note: If from_key is None then we return in topological order. This
+        # is because in that case we're using this as a "get the last few messages
+        # in a room" function, rather than "get new messages since last sync"
         if from_key is not None:
             from_id = RoomStreamToken.parse_stream_token(from_key).stream
         else:
@@ -217,8 +220,8 @@ class StreamStore(SQLBaseStore):
                     " room_id = ?"
                     " AND not outlier"
                     " AND stream_ordering <= ?"
-                    " ORDER BY stream_ordering %s LIMIT ?"
-                ) % (order,)
+                    " ORDER BY topological_ordering %s, stream_ordering %s LIMIT ?"
+                ) % (order, order,)
                 txn.execute(sql, (room_id, to_id, limit))
 
             rows = self.cursor_to_dict(txn)
@@ -232,7 +235,7 @@ class StreamStore(SQLBaseStore):
             get_prev_content=True
         )
 
-        self._set_before_and_after(ret, rows, topo_order=False)
+        self._set_before_and_after(ret, rows, topo_order=from_id is None)
 
         if order.lower() == "desc":
             ret.reverse()
@@ -462,9 +465,25 @@ class StreamStore(SQLBaseStore):
 
         defer.returnValue((events, token))
 
-    @cachedInlineCallbacks(num_args=4)
+    @defer.inlineCallbacks
     def get_recent_events_for_room(self, room_id, limit, end_token, from_token=None):
+        rows, token = yield self.get_recent_event_ids_for_room(
+            room_id, limit, end_token, from_token
+        )
+
+        logger.debug("stream before")
+        events = yield self._get_events(
+            [r["event_id"] for r in rows],
+            get_prev_content=True
+        )
+        logger.debug("stream after")
+
+        self._set_before_and_after(events, rows)
 
+        defer.returnValue((events, token))
+
+    @cached(num_args=4)
+    def get_recent_event_ids_for_room(self, room_id, limit, end_token, from_token=None):
         end_token = RoomStreamToken.parse_stream_token(end_token)
 
         if from_token is None:
@@ -514,24 +533,13 @@ class StreamStore(SQLBaseStore):
 
             return rows, token
 
-        rows, token = yield self.runInteraction(
+        return self.runInteraction(
             "get_recent_events_for_room", get_recent_events_for_room_txn
         )
 
-        logger.debug("stream before")
-        events = yield self._get_events(
-            [r["event_id"] for r in rows],
-            get_prev_content=True
-        )
-        logger.debug("stream after")
-
-        self._set_before_and_after(events, rows)
-
-        defer.returnValue((events, token))
-
     @defer.inlineCallbacks
     def get_room_events_max_id(self, direction='f'):
-        token = yield self._stream_id_gen.get_max_token(self)
+        token = yield self._stream_id_gen.get_max_token()
         if direction != 'b':
             defer.returnValue("s%d" % (token,))
         else: