Increase DB/CPU perf of _is_server_still_joined check. (#6936)

* Increase DB/CPU perf of `_is_server_still_joined` check.

For rooms with large amount of state a single user leaving could cause
us to go and load a lot of membership events and then pull out
membership state in a large number of batches.

* Newsfile

* Update synapse/storage/persist_events.py

Co-Authored-By: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>

* Fix adding if too soon

* Update docstring

* Review comments

* Woops typo

Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>
This commit is contained in:
Erik Johnston 2020-02-19 10:15:49 +00:00 committed by GitHub
parent 5e4a438556
commit 0d0bc35792
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3 changed files with 60 additions and 15 deletions

1
changelog.d/6936.misc Normal file
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@ -0,0 +1 @@
Increase DB/CPU perf of `_is_server_still_joined` check.

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@ -868,6 +868,37 @@ class RoomMemberWorkerStore(EventsWorkerStore):
desc="get_membership_from_event_ids",
)
async def is_local_host_in_room_ignoring_users(
self, room_id: str, ignore_users: Collection[str]
) -> bool:
"""Check if there are any local users, excluding those in the given
list, in the room.
"""
clause, args = make_in_list_sql_clause(
self.database_engine, "user_id", ignore_users
)
sql = """
SELECT 1 FROM local_current_membership
WHERE
room_id = ? AND membership = ?
AND NOT (%s)
LIMIT 1
""" % (
clause,
)
def _is_local_host_in_room_ignoring_users_txn(txn):
txn.execute(sql, (room_id, Membership.JOIN, *args))
return bool(txn.fetchone())
return await self.db.runInteraction(
"is_local_host_in_room_ignoring_users",
_is_local_host_in_room_ignoring_users_txn,
)
class RoomMemberBackgroundUpdateStore(SQLBaseStore):
def __init__(self, database: Database, db_conn, hs):

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@ -727,6 +727,7 @@ class EventsPersistenceStorage(object):
# Check if any of the given events are a local join that appear in the
# current state
events_to_check = [] # Event IDs that aren't an event we're persisting
for (typ, state_key), event_id in delta.to_insert.items():
if typ != EventTypes.Member or not self.is_mine_id(state_key):
continue
@ -736,8 +737,33 @@ class EventsPersistenceStorage(object):
if event.membership == Membership.JOIN:
return True
# There's been a change of membership but we don't have a local join
# event in the new events, so we need to check the full state.
# The event is not in `ev_ctx_rm`, so we need to pull it out of
# the DB.
events_to_check.append(event_id)
# Check if any of the changes that we don't have events for are joins.
if events_to_check:
rows = await self.main_store.get_membership_from_event_ids(events_to_check)
is_still_joined = any(row["membership"] == Membership.JOIN for row in rows)
if is_still_joined:
return True
# None of the new state events are local joins, so we check the database
# to see if there are any other local users in the room. We ignore users
# whose state has changed as we've already their new state above.
users_to_ignore = [
state_key
for _, state_key in itertools.chain(delta.to_insert, delta.to_delete)
if self.is_mine_id(state_key)
]
if await self.main_store.is_local_host_in_room_ignoring_users(
room_id, users_to_ignore
):
return True
# The server will leave the room, so we go and find out which remote
# users will still be joined when we leave.
if current_state is None:
current_state = await self.main_store.get_current_state_ids(room_id)
current_state = dict(current_state)
@ -746,19 +772,6 @@ class EventsPersistenceStorage(object):
current_state.update(delta.to_insert)
event_ids = [
event_id
for (typ, state_key,), event_id in current_state.items()
if typ == EventTypes.Member and self.is_mine_id(state_key)
]
rows = await self.main_store.get_membership_from_event_ids(event_ids)
is_still_joined = any(row["membership"] == Membership.JOIN for row in rows)
if is_still_joined:
return True
# The server will leave the room, so we go and find out which remote
# users will still be joined when we leave.
remote_event_ids = [
event_id
for (typ, state_key,), event_id in current_state.items()