Fix perf of `wait_for_stream_positions` (#16148)

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Erik Johnston 2023-08-22 16:11:22 +01:00 committed by GitHub
parent 0ba17777be
commit 803f63df1c
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2 changed files with 13 additions and 7 deletions

1
changelog.d/16148.bugfix Normal file
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@ -0,0 +1 @@
Fix performance degredation when there are a lot of in-flight replication requests.

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@ -14,7 +14,9 @@
"""A replication client for use by synapse workers.
"""
import logging
from typing import TYPE_CHECKING, Dict, Iterable, List, Optional, Set, Tuple
from typing import TYPE_CHECKING, Dict, Iterable, Optional, Set, Tuple
from sortedcontainers import SortedList
from twisted.internet import defer
from twisted.internet.defer import Deferred
@ -86,7 +88,9 @@ class ReplicationDataHandler:
# Map from stream and instance to list of deferreds waiting for the stream to
# arrive at a particular position. The lists are sorted by stream position.
self._streams_to_waiters: Dict[Tuple[str, str], List[Tuple[int, Deferred]]] = {}
self._streams_to_waiters: Dict[
Tuple[str, str], SortedList[Tuple[int, Deferred]]
] = {}
async def on_rdata(
self, stream_name: str, instance_name: str, token: int, rows: list
@ -238,7 +242,9 @@ class ReplicationDataHandler:
# Notify any waiting deferreds. The list is ordered by position so we
# just iterate through the list until we reach a position that is
# greater than the received row position.
waiting_list = self._streams_to_waiters.get((stream_name, instance_name), [])
waiting_list = self._streams_to_waiters.get((stream_name, instance_name))
if not waiting_list:
return
# Index of first item with a position after the current token, i.e we
# have called all deferreds before this index. If not overwritten by
@ -262,7 +268,7 @@ class ReplicationDataHandler:
# Drop all entries in the waiting list that were called in the above
# loop. (This maintains the order so no need to resort)
waiting_list[:] = waiting_list[index_of_first_deferred_not_called:]
del waiting_list[:index_of_first_deferred_not_called]
for deferred in deferreds_to_callback:
try:
@ -322,11 +328,10 @@ class ReplicationDataHandler:
)
waiting_list = self._streams_to_waiters.setdefault(
(stream_name, instance_name), []
(stream_name, instance_name), SortedList(key=lambda t: t[0])
)
waiting_list.append((position, deferred))
waiting_list.sort(key=lambda t: t[0])
waiting_list.add((position, deferred))
# We measure here to get in flight counts and average waiting time.
with Measure(self._clock, "repl.wait_for_stream_position"):