From 6d7523ef1484ec56f4a6dffdd2ea3d8736b4cc98 Mon Sep 17 00:00:00 2001 From: Patrick Cloke Date: Tue, 22 Nov 2022 09:41:09 -0500 Subject: [PATCH] Batch fetch bundled references (#14508) Avoid an n+1 query problem and fetch the bundled aggregations for m.reference relations in a single query instead of a query per event. This applies similar logic for as was previously done for edits in 8b309adb436c162510ed1402f33b8741d71fc058 (#11660; threads in b65acead428653b988351ae8d7b22127a22039cd (#11752); and annotations in 1799a54a545618782840a60950ef4b64da9ee24d (#14491). --- changelog.d/14508.feature | 1 + synapse/handlers/relations.py | 128 +++++++++----------- synapse/storage/databases/main/cache.py | 1 + synapse/storage/databases/main/events.py | 4 + synapse/storage/databases/main/relations.py | 74 +++++++++-- tests/rest/client/test_relations.py | 4 +- 6 files changed, 133 insertions(+), 79 deletions(-) create mode 100644 changelog.d/14508.feature diff --git a/changelog.d/14508.feature b/changelog.d/14508.feature new file mode 100644 index 000000000..4fca7282f --- /dev/null +++ b/changelog.d/14508.feature @@ -0,0 +1 @@ +Reduce database load of [Client-Server endpoints](https://spec.matrix.org/v1.4/client-server-api/#aggregations) which return bundled aggregations. diff --git a/synapse/handlers/relations.py b/synapse/handlers/relations.py index ca94239f6..8414be587 100644 --- a/synapse/handlers/relations.py +++ b/synapse/handlers/relations.py @@ -13,16 +13,7 @@ # limitations under the License. import enum import logging -from typing import ( - TYPE_CHECKING, - Collection, - Dict, - FrozenSet, - Iterable, - List, - Optional, - Tuple, -) +from typing import TYPE_CHECKING, Collection, Dict, FrozenSet, Iterable, List, Optional import attr @@ -32,7 +23,7 @@ from synapse.events import EventBase, relation_from_event from synapse.logging.opentracing import trace from synapse.storage.databases.main.relations import ThreadsNextBatch, _RelatedEvent from synapse.streams.config import PaginationConfig -from synapse.types import JsonDict, Requester, StreamToken, UserID +from synapse.types import JsonDict, Requester, UserID from synapse.visibility import filter_events_for_client if TYPE_CHECKING: @@ -181,40 +172,6 @@ class RelationsHandler: return return_value - async def get_relations_for_event( - self, - event_id: str, - event: EventBase, - room_id: str, - relation_type: str, - ignored_users: FrozenSet[str] = frozenset(), - ) -> Tuple[List[_RelatedEvent], Optional[StreamToken]]: - """Get a list of events which relate to an event, ordered by topological ordering. - - Args: - event_id: Fetch events that relate to this event ID. - event: The matching EventBase to event_id. - room_id: The room the event belongs to. - relation_type: The type of relation. - ignored_users: The users ignored by the requesting user. - - Returns: - List of event IDs that match relations requested. The rows are of - the form `{"event_id": "..."}`. - """ - - # Call the underlying storage method, which is cached. - related_events, next_token = await self._main_store.get_relations_for_event( - event_id, event, room_id, relation_type, direction="f" - ) - - # Filter out ignored users and convert to the expected format. - related_events = [ - event for event in related_events if event.sender not in ignored_users - ] - - return related_events, next_token - async def redact_events_related_to( self, requester: Requester, @@ -329,6 +286,46 @@ class RelationsHandler: return filtered_results + async def get_references_for_events( + self, event_ids: Collection[str], ignored_users: FrozenSet[str] = frozenset() + ) -> Dict[str, List[_RelatedEvent]]: + """Get a list of references to the given events. + + Args: + event_ids: Fetch events that relate to this event ID. + ignored_users: The users ignored by the requesting user. + + Returns: + A map of event IDs to a list related events. + """ + + related_events = await self._main_store.get_references_for_events(event_ids) + + # Avoid additional logic if there are no ignored users. + if not ignored_users: + return { + event_id: results + for event_id, results in related_events.items() + if results + } + + # Filter out ignored users. + results = {} + for event_id, events in related_events.items(): + # If no references, skip. + if not events: + continue + + # Filter ignored users out. + events = [event for event in events if event.sender not in ignored_users] + # If there are no events left, skip this event. + if not events: + continue + + results[event_id] = events + + return results + async def _get_threads_for_events( self, events_by_id: Dict[str, EventBase], @@ -412,14 +409,18 @@ class RelationsHandler: if event is None: continue - potential_events, _ = await self.get_relations_for_event( - event_id, - event, - room_id, - RelationTypes.THREAD, - ignored_users, + # Attempt to find another event to use as the latest event. + potential_events, _ = await self._main_store.get_relations_for_event( + event_id, event, room_id, RelationTypes.THREAD, direction="f" ) + # Filter out ignored users. + potential_events = [ + event + for event in potential_events + if event.sender not in ignored_users + ] + # If all found events are from ignored users, do not include # a summary of the thread. if not potential_events: @@ -534,27 +535,16 @@ class RelationsHandler: "chunk": annotations } - # Fetch other relations per event. - for event in events_by_id.values(): - # Fetch any references to bundle with this event. - references, next_token = await self.get_relations_for_event( - event.event_id, - event, - event.room_id, - RelationTypes.REFERENCE, - ignored_users=ignored_users, - ) + # Fetch any references to bundle with this event. + references_by_event_id = await self.get_references_for_events( + events_by_id.keys(), ignored_users=ignored_users + ) + for event_id, references in references_by_event_id.items(): if references: - aggregations = results.setdefault(event.event_id, BundledAggregations()) - aggregations.references = { + results.setdefault(event_id, BundledAggregations()).references = { "chunk": [{"event_id": ev.event_id} for ev in references] } - if next_token: - aggregations.references["next_batch"] = await next_token.to_string( - self._main_store - ) - # Fetch any edits (but not for redacted events). # # Note that there is no use in limiting edits by ignored users since the @@ -600,7 +590,7 @@ class RelationsHandler: room_id, requester, allow_departed_users=True ) - # Note that ignored users are not passed into get_relations_for_event + # Note that ignored users are not passed into get_threads # below. Ignored users are handled in filter_events_for_client (and by # not passing them in here we should get a better cache hit rate). thread_roots, next_batch = await self._main_store.get_threads( diff --git a/synapse/storage/databases/main/cache.py b/synapse/storage/databases/main/cache.py index ddb739771..a58668a38 100644 --- a/synapse/storage/databases/main/cache.py +++ b/synapse/storage/databases/main/cache.py @@ -259,6 +259,7 @@ class CacheInvalidationWorkerStore(SQLBaseStore): if relates_to: self._attempt_to_invalidate_cache("get_relations_for_event", (relates_to,)) + self._attempt_to_invalidate_cache("get_references_for_event", (relates_to,)) self._attempt_to_invalidate_cache( "get_aggregation_groups_for_event", (relates_to,) ) diff --git a/synapse/storage/databases/main/events.py b/synapse/storage/databases/main/events.py index d68f127f9..0f097a292 100644 --- a/synapse/storage/databases/main/events.py +++ b/synapse/storage/databases/main/events.py @@ -2049,6 +2049,10 @@ class PersistEventsStore: self.store._invalidate_cache_and_stream( txn, self.store.get_aggregation_groups_for_event, (redacted_relates_to,) ) + if rel_type == RelationTypes.REFERENCE: + self.store._invalidate_cache_and_stream( + txn, self.store.get_references_for_event, (redacted_relates_to,) + ) if rel_type == RelationTypes.REPLACE: self.store._invalidate_cache_and_stream( txn, self.store.get_applicable_edit, (redacted_relates_to,) diff --git a/synapse/storage/databases/main/relations.py b/synapse/storage/databases/main/relations.py index f96a16956..aea96e9d2 100644 --- a/synapse/storage/databases/main/relations.py +++ b/synapse/storage/databases/main/relations.py @@ -82,8 +82,6 @@ class _RelatedEvent: event_id: str # The sender of the related event. sender: str - topological_ordering: Optional[int] - stream_ordering: int class RelationsWorkerStore(SQLBaseStore): @@ -246,13 +244,17 @@ class RelationsWorkerStore(SQLBaseStore): txn.execute(sql, where_args + [limit + 1]) events = [] - for event_id, relation_type, sender, topo_ordering, stream_ordering in txn: + topo_orderings: List[int] = [] + stream_orderings: List[int] = [] + for event_id, relation_type, sender, topo_ordering, stream_ordering in cast( + List[Tuple[str, str, str, int, int]], txn + ): # Do not include edits for redacted events as they leak event # content. if not is_redacted or relation_type != RelationTypes.REPLACE: - events.append( - _RelatedEvent(event_id, sender, topo_ordering, stream_ordering) - ) + events.append(_RelatedEvent(event_id, sender)) + topo_orderings.append(topo_ordering) + stream_orderings.append(stream_ordering) # If there are more events, generate the next pagination key from the # last event returned. @@ -261,9 +263,11 @@ class RelationsWorkerStore(SQLBaseStore): # Instead of using the last row (which tells us there is more # data), use the last row to be returned. events = events[:limit] + topo_orderings = topo_orderings[:limit] + stream_orderings = stream_orderings[:limit] - topo = events[-1].topological_ordering - token = events[-1].stream_ordering + topo = topo_orderings[-1] + token = stream_orderings[-1] if direction == "b": # Tokens are positions between events. # This token points *after* the last event in the chunk. @@ -530,6 +534,60 @@ class RelationsWorkerStore(SQLBaseStore): "get_aggregation_groups_for_users", _get_aggregation_groups_for_users_txn ) + @cached() + async def get_references_for_event(self, event_id: str) -> List[JsonDict]: + raise NotImplementedError() + + @cachedList(cached_method_name="get_references_for_event", list_name="event_ids") + async def get_references_for_events( + self, event_ids: Collection[str] + ) -> Mapping[str, Optional[List[_RelatedEvent]]]: + """Get a list of references to the given events. + + Args: + event_ids: Fetch events that relate to these event IDs. + + Returns: + A map of event IDs to a list of related event IDs (and their senders). + """ + + clause, args = make_in_list_sql_clause( + self.database_engine, "relates_to_id", event_ids + ) + args.append(RelationTypes.REFERENCE) + + sql = f""" + SELECT relates_to_id, ref.event_id, ref.sender + FROM events AS ref + INNER JOIN event_relations USING (event_id) + INNER JOIN events AS parent ON + parent.event_id = relates_to_id + AND parent.room_id = ref.room_id + WHERE + {clause} + AND relation_type = ? + ORDER BY ref.topological_ordering, ref.stream_ordering + """ + + def _get_references_for_events_txn( + txn: LoggingTransaction, + ) -> Mapping[str, List[_RelatedEvent]]: + txn.execute(sql, args) + + result: Dict[str, List[_RelatedEvent]] = {} + for relates_to_id, event_id, sender in cast( + List[Tuple[str, str, str]], txn + ): + result.setdefault(relates_to_id, []).append( + _RelatedEvent(event_id, sender) + ) + + return result + + return await self.db_pool.runInteraction( + "_get_references_for_events_txn", _get_references_for_events_txn + ) + @cached() def get_applicable_edit(self, event_id: str) -> Optional[EventBase]: raise NotImplementedError() diff --git a/tests/rest/client/test_relations.py b/tests/rest/client/test_relations.py index 2d2b68354..b86f341ff 100644 --- a/tests/rest/client/test_relations.py +++ b/tests/rest/client/test_relations.py @@ -1108,7 +1108,7 @@ class BundledAggregationsTestCase(BaseRelationsTestCase): # The "user" sent the root event and is making queries for the bundled # aggregations: they have participated. - self._test_bundled_aggregations(RelationTypes.THREAD, _gen_assert(True), 8) + self._test_bundled_aggregations(RelationTypes.THREAD, _gen_assert(True), 7) # The "user2" sent replies in the thread and is making queries for the # bundled aggregations: they have participated. # @@ -1170,7 +1170,7 @@ class BundledAggregationsTestCase(BaseRelationsTestCase): bundled_aggregations["latest_event"].get("unsigned"), ) - self._test_bundled_aggregations(RelationTypes.THREAD, assert_thread, 8) + self._test_bundled_aggregations(RelationTypes.THREAD, assert_thread, 7) def test_nested_thread(self) -> None: """