From 587f07543fcf604da58903b22a7448e631d797ea Mon Sep 17 00:00:00 2001
From: Erik Johnston <erikj@jki.re>
Date: Thu, 4 May 2017 15:07:27 +0100
Subject: [PATCH] Revert "Prefill state caches"

---
 synapse/storage/_base.py  |  8 ++++----
 synapse/storage/events.py | 16 +++++-----------
 synapse/storage/state.py  | 12 ------------
 3 files changed, 9 insertions(+), 27 deletions(-)

diff --git a/synapse/storage/_base.py b/synapse/storage/_base.py
index 58b73af7d2..c659004e8d 100644
--- a/synapse/storage/_base.py
+++ b/synapse/storage/_base.py
@@ -60,12 +60,12 @@ class LoggingTransaction(object):
         object.__setattr__(self, "database_engine", database_engine)
         object.__setattr__(self, "after_callbacks", after_callbacks)
 
-    def call_after(self, callback, *args, **kwargs):
+    def call_after(self, callback, *args):
         """Call the given callback on the main twisted thread after the
         transaction has finished. Used to invalidate the caches on the
         correct thread.
         """
-        self.after_callbacks.append((callback, args, kwargs))
+        self.after_callbacks.append((callback, args))
 
     def __getattr__(self, name):
         return getattr(self.txn, name)
@@ -319,8 +319,8 @@ class SQLBaseStore(object):
                     inner_func, *args, **kwargs
                 )
         finally:
-            for after_callback, after_args, after_kwargs in after_callbacks:
-                after_callback(*after_args, **after_kwargs)
+            for after_callback, after_args in after_callbacks:
+                after_callback(*after_args)
         defer.returnValue(result)
 
     @defer.inlineCallbacks
diff --git a/synapse/storage/events.py b/synapse/storage/events.py
index d946024c9b..98707d40ee 100644
--- a/synapse/storage/events.py
+++ b/synapse/storage/events.py
@@ -374,12 +374,6 @@ class EventsStore(SQLBaseStore):
                     new_forward_extremeties=new_forward_extremeties,
                 )
                 persist_event_counter.inc_by(len(chunk))
-
-                for room_id, (_, _, new_state) in current_state_for_room.iteritems():
-                    self.get_current_state_ids.prefill(
-                        (room_id, ), new_state
-                    )
-
                 for event, context in chunk:
                     if context.app_service:
                         origin_type = "local"
@@ -441,10 +435,10 @@ class EventsStore(SQLBaseStore):
         Assumes that we are only persisting events for one room at a time.
 
         Returns:
-            3-tuple (to_delete, to_insert, new_state) where both are state dicts,
-            i.e. (type, state_key) -> event_id. `to_delete` are the entries to
+            2-tuple (to_delete, to_insert) where both are state dicts, i.e.
+            (type, state_key) -> event_id. `to_delete` are the entries to
             first be deleted from current_state_events, `to_insert` are entries
-            to insert. `new_state` is the full set of state.
+            to insert.
             May return None if there are no changes to be applied.
         """
         # Now we need to work out the different state sets for
@@ -551,7 +545,7 @@ class EventsStore(SQLBaseStore):
             if ev_id in events_to_insert
         }
 
-        defer.returnValue((to_delete, to_insert, current_state))
+        defer.returnValue((to_delete, to_insert))
 
     @defer.inlineCallbacks
     def get_event(self, event_id, check_redacted=True,
@@ -704,7 +698,7 @@ class EventsStore(SQLBaseStore):
 
     def _update_current_state_txn(self, txn, state_delta_by_room):
         for room_id, current_state_tuple in state_delta_by_room.iteritems():
-                to_delete, to_insert, _ = current_state_tuple
+                to_delete, to_insert = current_state_tuple
                 txn.executemany(
                     "DELETE FROM current_state_events WHERE event_id = ?",
                     [(ev_id,) for ev_id in to_delete.itervalues()],
diff --git a/synapse/storage/state.py b/synapse/storage/state.py
index 03981f5d2b..a16afa8df5 100644
--- a/synapse/storage/state.py
+++ b/synapse/storage/state.py
@@ -227,18 +227,6 @@ class StateStore(SQLBaseStore):
                     ],
                 )
 
-            # Prefill the state group cache with this group.
-            # It's fine to use the sequence like this as the state group map
-            # is immutable. (If the map wasn't immutable then this prefill could
-            # race with another update)
-            txn.call_after(
-                self._state_group_cache.update,
-                self._state_group_cache.sequence,
-                key=context.state_group,
-                value=context.current_state_ids,
-                full=True,
-            )
-
         self._simple_insert_many_txn(
             txn,
             table="event_to_state_groups",