From 49f4bc470993136ee4f5af7c34bee5ddc22768bd Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Mon, 27 Feb 2017 18:33:41 +0000
Subject: [PATCH 1/3] Don't fetch current state in common case

Currently we fetch the list of current state events whenever we send
something in a room. This is overkill for the common case of persisting
a simple chain of non-state events, so lets handle that case specially.
---
 synapse/storage/events.py | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/synapse/storage/events.py b/synapse/storage/events.py
index c88f689d3a..a4ce71cb27 100644
--- a/synapse/storage/events.py
+++ b/synapse/storage/events.py
@@ -311,6 +311,23 @@ class EventsStore(SQLBaseStore):
 
                             new_forward_extremeties[room_id] = new_latest_event_ids
 
+                            len_1 = (
+                                len(latest_event_ids) == 1
+                                and len(new_latest_event_ids) == 1
+                            )
+                            if len_1:
+                                all_single_prev_not_state = any(
+                                    len(event.prev_events) == 1
+                                    and not event.is_state()
+                                    for event, ctx in ev_ctx_rm
+                                    if not event.internal_metadata.is_outlier()
+                                    and not ctx.rejected
+                                )
+                                # Don't bother calculating state if they're just
+                                # a long chain of single ancestor non-state events.
+                                if all_single_prev_not_state:
+                                    continue
+
                             state = yield self._calculate_state_delta(
                                 room_id, ev_ctx_rm, new_latest_event_ids
                             )

From c0d6045776909a83181a4a925198c58e625ea4a2 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Mon, 27 Feb 2017 18:45:24 +0000
Subject: [PATCH 2/3] It should be all

---
 synapse/storage/events.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/synapse/storage/events.py b/synapse/storage/events.py
index a4ce71cb27..08807deba9 100644
--- a/synapse/storage/events.py
+++ b/synapse/storage/events.py
@@ -316,7 +316,7 @@ class EventsStore(SQLBaseStore):
                                 and len(new_latest_event_ids) == 1
                             )
                             if len_1:
-                                all_single_prev_not_state = any(
+                                all_single_prev_not_state = all(
                                     len(event.prev_events) == 1
                                     and not event.is_state()
                                     for event, ctx in ev_ctx_rm

From a41dce8f8ae8bfb957a5830783e00437b4636c10 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Mon, 27 Feb 2017 18:54:43 +0000
Subject: [PATCH 3/3] Remove needless check

---
 synapse/storage/events.py | 2 --
 1 file changed, 2 deletions(-)

diff --git a/synapse/storage/events.py b/synapse/storage/events.py
index 08807deba9..db01eb6d14 100644
--- a/synapse/storage/events.py
+++ b/synapse/storage/events.py
@@ -320,8 +320,6 @@ class EventsStore(SQLBaseStore):
                                     len(event.prev_events) == 1
                                     and not event.is_state()
                                     for event, ctx in ev_ctx_rm
-                                    if not event.internal_metadata.is_outlier()
-                                    and not ctx.rejected
                                 )
                                 # Don't bother calculating state if they're just
                                 # a long chain of single ancestor non-state events.