Merge pull request #2054 from matrix-org/erikj/user_iter_cursor

Reduce some CPU work on DB threads

1 files changed, 33 insertions, 33 deletions

diff --git a/synapse/storage/state.py b/synapse/storage/state.py
index 1b42bea07a..314216f039 100644
--- a/synapse/storage/state.py
+++ b/synapse/storage/state.py
@@ -90,7 +90,7 @@ class StateStore(SQLBaseStore):
             event_ids,
         )
 
-        groups = set(event_to_groups.values())
+        groups = set(event_to_groups.itervalues())
         group_to_state = yield self._get_state_for_groups(groups)
 
         defer.returnValue(group_to_state)
@@ -108,17 +108,18 @@ class StateStore(SQLBaseStore):
 
         state_event_map = yield self.get_events(
             [
-                ev_id for group_ids in group_to_ids.values()
-                for ev_id in group_ids.values()
+                ev_id for group_ids in group_to_ids.itervalues()
+                for ev_id in group_ids.itervalues()
             ],
             get_prev_content=False
         )
 
         defer.returnValue({
             group: [
-                state_event_map[v] for v in event_id_map.values() if v in state_event_map
+                state_event_map[v] for v in event_id_map.itervalues()
+                if v in state_event_map
             ]
-            for group, event_id_map in group_to_ids.items()
+            for group, event_id_map in group_to_ids.iteritems()
         })
 
     def _have_persisted_state_group_txn(self, txn, state_group):
@@ -190,7 +191,7 @@ class StateStore(SQLBaseStore):
                             "state_key": key[1],
                             "event_id": state_id,
                         }
-                        for key, state_id in context.delta_ids.items()
+                        for key, state_id in context.delta_ids.iteritems()
                     ],
                 )
             else:
@@ -205,7 +206,7 @@ class StateStore(SQLBaseStore):
                             "state_key": key[1],
                             "event_id": state_id,
                         }
-                        for key, state_id in context.current_state_ids.items()
+                        for key, state_id in context.current_state_ids.iteritems()
                     ],
                 )
 
@@ -217,7 +218,7 @@ class StateStore(SQLBaseStore):
                     "state_group": state_group_id,
                     "event_id": event_id,
                 }
-                for event_id, state_group_id in state_groups.items()
+                for event_id, state_group_id in state_groups.iteritems()
             ],
         )
 
@@ -341,10 +342,10 @@ class StateStore(SQLBaseStore):
                     args.extend(where_args)
 
                     txn.execute(sql % (where_clause,), args)
-                    rows = self.cursor_to_dict(txn)
-                    for row in rows:
-                        key = (row["type"], row["state_key"])
-                        results[group][key] = row["event_id"]
+                    for row in txn:
+                        typ, state_key, event_id = row
+                        key = (typ, state_key)
+                        results[group][key] = event_id
         else:
             if types is not None:
                 where_clause = "AND (%s)" % (
@@ -373,12 +374,11 @@ class StateStore(SQLBaseStore):
                         " WHERE state_group = ? %s" % (where_clause,),
                         args
                     )
-                    rows = txn.fetchall()
-                    results[group].update({
-                        (typ, state_key): event_id
-                        for typ, state_key, event_id in rows
+                    results[group].update(
+                        ((typ, state_key), event_id)
+                        for typ, state_key, event_id in txn
                         if (typ, state_key) not in results[group]
-                    })
+                    )
 
                     # If the lengths match then we must have all the types,
                     # so no need to go walk further down the tree.
@@ -415,21 +415,21 @@ class StateStore(SQLBaseStore):
             event_ids,
         )
 
-        groups = set(event_to_groups.values())
+        groups = set(event_to_groups.itervalues())
         group_to_state = yield self._get_state_for_groups(groups, types)
 
         state_event_map = yield self.get_events(
-            [ev_id for sd in group_to_state.values() for ev_id in sd.values()],
+            [ev_id for sd in group_to_state.itervalues() for ev_id in sd.itervalues()],
             get_prev_content=False
         )
 
         event_to_state = {
             event_id: {
                 k: state_event_map[v]
-                for k, v in group_to_state[group].items()
+                for k, v in group_to_state[group].iteritems()
                 if v in state_event_map
             }
-            for event_id, group in event_to_groups.items()
+            for event_id, group in event_to_groups.iteritems()
         }
 
         defer.returnValue({event: event_to_state[event] for event in event_ids})
@@ -452,12 +452,12 @@ class StateStore(SQLBaseStore):
             event_ids,
         )
 
-        groups = set(event_to_groups.values())
+        groups = set(event_to_groups.itervalues())
         group_to_state = yield self._get_state_for_groups(groups, types)
 
         event_to_state = {
             event_id: group_to_state[group]
-            for event_id, group in event_to_groups.items()
+            for event_id, group in event_to_groups.iteritems()
         }
 
         defer.returnValue({event: event_to_state[event] for event in event_ids})
@@ -569,7 +569,7 @@ class StateStore(SQLBaseStore):
         got_all = not (missing_types or types is None)
 
         return {
-            k: v for k, v in state_dict_ids.items()
+            k: v for k, v in state_dict_ids.iteritems()
             if include(k[0], k[1])
         }, missing_types, got_all
 
@@ -628,7 +628,7 @@ class StateStore(SQLBaseStore):
 
             # Now we want to update the cache with all the things we fetched
             # from the database.
-            for group, group_state_dict in group_to_state_dict.items():
+            for group, group_state_dict in group_to_state_dict.iteritems():
                 if types:
                     # We delibrately put key -> None mappings into the cache to
                     # cache absence of the key, on the assumption that if we've
@@ -643,10 +643,10 @@ class StateStore(SQLBaseStore):
                 else:
                     state_dict = results[group]
 
-                state_dict.update({
-                    (intern_string(k[0]), intern_string(k[1])): v
-                    for k, v in group_state_dict.items()
-                })
+                state_dict.update(
+                    ((intern_string(k[0]), intern_string(k[1])), v)
+                    for k, v in group_state_dict.iteritems()
+                )
 
                 self._state_group_cache.update(
                     cache_seq_num,
@@ -657,10 +657,10 @@ class StateStore(SQLBaseStore):
 
         # Remove all the entries with None values. The None values were just
         # used for bookkeeping in the cache.
-        for group, state_dict in results.items():
+        for group, state_dict in results.iteritems():
             results[group] = {
                 key: event_id
-                for key, event_id in state_dict.items()
+                for key, event_id in state_dict.iteritems()
                 if event_id
             }
 
@@ -749,7 +749,7 @@ class StateStore(SQLBaseStore):
                         # of keys
 
                         delta_state = {
-                            key: value for key, value in curr_state.items()
+                            key: value for key, value in curr_state.iteritems()
                             if prev_state.get(key, None) != value
                         }
 
@@ -789,7 +789,7 @@ class StateStore(SQLBaseStore):
                                     "state_key": key[1],
                                     "event_id": state_id,
                                 }
-                                for key, state_id in delta_state.items()
+                                for key, state_id in delta_state.iteritems()
                             ],
                         )