Fix race calling /members?at= (#14817)

Fixes #14814
This commit is contained in:
Erik Johnston 2023-01-12 10:29:09 +00:00 committed by GitHub
parent 3952297f6f
commit 84ce93c12f
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2 changed files with 60 additions and 6 deletions

1
changelog.d/14817.bugfix Normal file
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@ -0,0 +1 @@
Fix race where calling `/members` or `/state` with an `at` parameter could fail for newly created rooms, when using multiple workers.

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@ -801,14 +801,67 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
before this stream ordering.
"""
last_row = await self.get_room_event_before_stream_ordering(
room_id=room_id,
stream_ordering=end_token.stream,
def get_last_event_in_room_before_stream_ordering_txn(
txn: LoggingTransaction,
) -> Optional[str]:
# We need to handle the fact that the stream tokens can be vector
# clocks. We do this by getting all rows between the minimum and
# maximum stream ordering in the token, plus one row less than the
# minimum stream ordering. We then filter the results against the
# token and return the first row that matches.
sql = """
SELECT * FROM (
SELECT instance_name, stream_ordering, topological_ordering, event_id
FROM events
LEFT JOIN rejections USING (event_id)
WHERE room_id = ?
AND ? < stream_ordering AND stream_ordering <= ?
AND NOT outlier
AND rejections.event_id IS NULL
ORDER BY stream_ordering DESC
) AS a
UNION
SELECT * FROM (
SELECT instance_name, stream_ordering, topological_ordering, event_id
FROM events
LEFT JOIN rejections USING (event_id)
WHERE room_id = ?
AND stream_ordering <= ?
AND NOT outlier
AND rejections.event_id IS NULL
ORDER BY stream_ordering DESC
LIMIT 1
) AS b
"""
txn.execute(
sql,
(
room_id,
end_token.stream,
end_token.get_max_stream_pos(),
room_id,
end_token.stream,
),
)
if last_row:
return last_row[2]
for instance_name, stream_ordering, topological_ordering, event_id in txn:
if _filter_results(
lower_token=None,
upper_token=end_token,
instance_name=instance_name,
topological_ordering=topological_ordering,
stream_ordering=stream_ordering,
):
return event_id
return None
return await self.db_pool.runInteraction(
"get_last_event_in_room_before_stream_ordering",
get_last_event_in_room_before_stream_ordering_txn,
)
async def get_current_room_stream_token_for_room_id(
self, room_id: str
) -> RoomStreamToken: