From a9c146ac53a40d191c0a2b3b1b8f6ceaea0eee79 Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <richard@matrix.org>
Date: Wed, 15 Dec 2021 13:08:24 +0000
Subject: [PATCH 1/2] Disable aggregation bundling on `/sync` responses
A partial revert of #11478. This turns out to have had a significant CPU impact
on initial-sync handling. For now, let's disable it, until we find a more
efficient way of achieving this.
---
changelog.d/11583.bugfix | 1 +
synapse/rest/client/sync.py | 8 +++++++-
2 files changed, 8 insertions(+), 1 deletion(-)
create mode 100644 changelog.d/11583.bugfix
diff --git a/changelog.d/11583.bugfix b/changelog.d/11583.bugfix
new file mode 100644
index 000000000000..d2ed113e2128
--- /dev/null
+++ b/changelog.d/11583.bugfix
@@ -0,0 +1 @@
+Fix a performance regression in `/sync` handling, introduced in 1.49.0.
diff --git a/synapse/rest/client/sync.py b/synapse/rest/client/sync.py
index 88e4f5e0630f..e556ff93e670 100644
--- a/synapse/rest/client/sync.py
+++ b/synapse/rest/client/sync.py
@@ -522,7 +522,13 @@ def serialize(events: Iterable[EventBase]) -> Awaitable[List[JsonDict]]:
time_now=time_now,
# Don't bother to bundle aggregations if the timeline is unlimited,
# as clients will have all the necessary information.
- bundle_aggregations=room.timeline.limited,
+ # bundle_aggregations=room.timeline.limited,
+ #
+ # richvdh 2021-12-15: disable this temporarily as it has too high an
+ # overhead for initialsyncs. We need to figure out a way that the
+ # bundling can be done *before* the events are stored in the
+ # SyncResponseCache so that this part can be synchronous.
+ bundle_aggregations=False,
token_id=token_id,
event_format=event_formatter,
only_event_fields=only_fields,
From eca24d7d2880f7eb7350d919d93c839c82da9a92 Mon Sep 17 00:00:00 2001
From: Patrick Cloke <patrickc@matrix.org>
Date: Wed, 15 Dec 2021 11:18:23 -0500
Subject: [PATCH 2/2] Fix tests.
---
synapse/rest/client/sync.py | 2 ++
tests/rest/client/test_relations.py | 10 +++++-----
2 files changed, 7 insertions(+), 5 deletions(-)
diff --git a/synapse/rest/client/sync.py b/synapse/rest/client/sync.py
index e556ff93e670..7f5846d38934 100644
--- a/synapse/rest/client/sync.py
+++ b/synapse/rest/client/sync.py
@@ -528,6 +528,8 @@ def serialize(events: Iterable[EventBase]) -> Awaitable[List[JsonDict]]:
# overhead for initialsyncs. We need to figure out a way that the
# bundling can be done *before* the events are stored in the
# SyncResponseCache so that this part can be synchronous.
+ #
+ # Ensure to re-enable the test at tests/rest/client/test_relations.py::RelationsTestCase.test_bundled_aggregations.
bundle_aggregations=False,
token_id=token_id,
event_format=event_formatter,
diff --git a/tests/rest/client/test_relations.py b/tests/rest/client/test_relations.py
index 397c12c2a6c5..1b58b73136c5 100644
--- a/tests/rest/client/test_relations.py
+++ b/tests/rest/client/test_relations.py
@@ -574,11 +574,11 @@ def _find_and_assert_event(events):
assert_bundle(channel.json_body["event"]["unsigned"].get("m.relations"))
# Request sync.
- channel = self.make_request("GET", "/sync", access_token=self.user_token)
- self.assertEquals(200, channel.code, channel.json_body)
- room_timeline = channel.json_body["rooms"]["join"][self.room]["timeline"]
- self.assertTrue(room_timeline["limited"])
- _find_and_assert_event(room_timeline["events"])
+ # channel = self.make_request("GET", "/sync", access_token=self.user_token)
+ # self.assertEquals(200, channel.code, channel.json_body)
+ # room_timeline = channel.json_body["rooms"]["join"][self.room]["timeline"]
+ # self.assertTrue(room_timeline["limited"])
+ # _find_and_assert_event(room_timeline["events"])
# Note that /relations is tested separately in test_aggregation_get_event_for_thread
# since it needs different data configured.