diff options
| -rw-r--r-- | changelog.d/13435.misc | 1 | ||||
| -rw-r--r-- | synapse/storage/databases/main/events_worker.py | 75 | ||||
| -rw-r--r-- | synapse/storage/databases/main/roommember.py | 2 | ||||
| -rw-r--r-- | synapse/util/caches/lrucache.py | 17 |
4 files changed, 87 insertions, 8 deletions
diff --git a/changelog.d/13435.misc b/changelog.d/13435.misc new file mode 100644 index 0000000000..c01b9136c8 --- /dev/null +++ b/changelog.d/13435.misc @@ -0,0 +1 @@ +Prevent unnecessary lookups to any external `get_event` cache. Contributed by Nick @ Beeper (@fizzadar). diff --git a/synapse/storage/databases/main/events_worker.py b/synapse/storage/databases/main/events_worker.py index 29c99c6357..e9ff6cfb34 100644 --- a/synapse/storage/databases/main/events_worker.py +++ b/synapse/storage/databases/main/events_worker.py @@ -600,7 +600,11 @@ class EventsWorkerStore(SQLBaseStore): Returns: map from event id to result """ - event_entry_map = await self._get_events_from_cache( + # Shortcut: check if we have any events in the *in memory* cache - this function + # may be called repeatedly for the same event so at this point we cannot reach + # out to any external cache for performance reasons. The external cache is + # checked later on in the `get_missing_events_from_cache_or_db` function below. + event_entry_map = self._get_events_from_local_cache( event_ids, ) @@ -632,7 +636,9 @@ class EventsWorkerStore(SQLBaseStore): if missing_events_ids: - async def get_missing_events_from_db() -> Dict[str, EventCacheEntry]: + async def get_missing_events_from_cache_or_db() -> Dict[ + str, EventCacheEntry + ]: """Fetches the events in `missing_event_ids` from the database. Also creates entries in `self._current_event_fetches` to allow @@ -657,10 +663,18 @@ class EventsWorkerStore(SQLBaseStore): # the events have been redacted, and if so pulling the redaction event # out of the database to check it. # + missing_events = {} try: - missing_events = await self._get_events_from_db( + # Try to fetch from any external cache. We already checked the + # in-memory cache above. + missing_events = await self._get_events_from_external_cache( missing_events_ids, ) + # Now actually fetch any remaining events from the DB + db_missing_events = await self._get_events_from_db( + missing_events_ids - missing_events.keys(), + ) + missing_events.update(db_missing_events) except Exception as e: with PreserveLoggingContext(): fetching_deferred.errback(e) @@ -679,7 +693,7 @@ class EventsWorkerStore(SQLBaseStore): # cancellations, since multiple `_get_events_from_cache_or_db` calls can # reuse the same fetch. missing_events: Dict[str, EventCacheEntry] = await delay_cancellation( - get_missing_events_from_db() + get_missing_events_from_cache_or_db() ) event_entry_map.update(missing_events) @@ -754,7 +768,54 @@ class EventsWorkerStore(SQLBaseStore): async def _get_events_from_cache( self, events: Iterable[str], update_metrics: bool = True ) -> Dict[str, EventCacheEntry]: - """Fetch events from the caches. + """Fetch events from the caches, both in memory and any external. + + May return rejected events. + + Args: + events: list of event_ids to fetch + update_metrics: Whether to update the cache hit ratio metrics + """ + event_map = self._get_events_from_local_cache( + events, update_metrics=update_metrics + ) + + missing_event_ids = (e for e in events if e not in event_map) + event_map.update( + await self._get_events_from_external_cache( + events=missing_event_ids, + update_metrics=update_metrics, + ) + ) + + return event_map + + async def _get_events_from_external_cache( + self, events: Iterable[str], update_metrics: bool = True + ) -> Dict[str, EventCacheEntry]: + """Fetch events from any configured external cache. + + May return rejected events. + + Args: + events: list of event_ids to fetch + update_metrics: Whether to update the cache hit ratio metrics + """ + event_map = {} + + for event_id in events: + ret = await self._get_event_cache.get_external( + (event_id,), None, update_metrics=update_metrics + ) + if ret: + event_map[event_id] = ret + + return event_map + + def _get_events_from_local_cache( + self, events: Iterable[str], update_metrics: bool = True + ) -> Dict[str, EventCacheEntry]: + """Fetch events from the local, in memory, caches. May return rejected events. @@ -766,7 +827,7 @@ class EventsWorkerStore(SQLBaseStore): for event_id in events: # First check if it's in the event cache - ret = await self._get_event_cache.get( + ret = self._get_event_cache.get_local( (event_id,), None, update_metrics=update_metrics ) if ret: @@ -788,7 +849,7 @@ class EventsWorkerStore(SQLBaseStore): # We add the entry back into the cache as we want to keep # recently queried events in the cache. - await self._get_event_cache.set((event_id,), cache_entry) + self._get_event_cache.set_local((event_id,), cache_entry) return event_map diff --git a/synapse/storage/databases/main/roommember.py b/synapse/storage/databases/main/roommember.py index e2cccc688c..93ff4816c8 100644 --- a/synapse/storage/databases/main/roommember.py +++ b/synapse/storage/databases/main/roommember.py @@ -896,7 +896,7 @@ class RoomMemberWorkerStore(EventsWorkerStore): # We don't update the event cache hit ratio as it completely throws off # the hit ratio counts. After all, we don't populate the cache if we # miss it here - event_map = await self._get_events_from_cache( + event_map = self._get_events_from_local_cache( member_event_ids, update_metrics=False ) diff --git a/synapse/util/caches/lrucache.py b/synapse/util/caches/lrucache.py index b3bdedb04c..aa93109d13 100644 --- a/synapse/util/caches/lrucache.py +++ b/synapse/util/caches/lrucache.py @@ -834,9 +834,26 @@ class AsyncLruCache(Generic[KT, VT]): ) -> Optional[VT]: return self._lru_cache.get(key, update_metrics=update_metrics) + async def get_external( + self, + key: KT, + default: Optional[T] = None, + update_metrics: bool = True, + ) -> Optional[VT]: + # This method should fetch from any configured external cache, in this case noop. + return None + + def get_local( + self, key: KT, default: Optional[T] = None, update_metrics: bool = True + ) -> Optional[VT]: + return self._lru_cache.get(key, update_metrics=update_metrics) + async def set(self, key: KT, value: VT) -> None: self._lru_cache.set(key, value) + def set_local(self, key: KT, value: VT) -> None: + self._lru_cache.set(key, value) + async def invalidate(self, key: KT) -> None: # This method should invalidate any external cache and then invalidate the LruCache. return self._lru_cache.invalidate(key) |