diff options
Diffstat (limited to 'synapse/storage/databases/main/stream.py')
| -rw-r--r-- | synapse/storage/databases/main/stream.py | 275 |
1 files changed, 190 insertions, 85 deletions
diff --git a/synapse/storage/databases/main/stream.py b/synapse/storage/databases/main/stream.py index 95775e3804..4989c960a6 100644 --- a/synapse/storage/databases/main/stream.py +++ b/synapse/storage/databases/main/stream.py @@ -51,6 +51,7 @@ from typing import ( Iterable, List, Optional, + Protocol, Set, Tuple, cast, @@ -59,7 +60,7 @@ from typing import ( import attr from immutabledict import immutabledict -from typing_extensions import Literal +from typing_extensions import Literal, assert_never from twisted.internet import defer @@ -97,6 +98,18 @@ _STREAM_TOKEN = "stream" _TOPOLOGICAL_TOKEN = "topological" +class PaginateFunction(Protocol): + async def __call__( + self, + *, + room_id: str, + from_key: RoomStreamToken, + to_key: Optional[RoomStreamToken] = None, + direction: Direction = Direction.BACKWARDS, + limit: int = 0, + ) -> Tuple[List[EventBase], RoomStreamToken]: ... + + # Used as return values for pagination APIs @attr.s(slots=True, frozen=True, auto_attribs=True) class _EventDictReturn: @@ -280,7 +293,7 @@ def generate_pagination_bounds( def generate_next_token( - direction: Direction, last_topo_ordering: int, last_stream_ordering: int + direction: Direction, last_topo_ordering: Optional[int], last_stream_ordering: int ) -> RoomStreamToken: """ Generate the next room stream token based on the currently returned data. @@ -447,7 +460,6 @@ def _filter_results_by_stream( The `instance_name` arg is optional to handle historic rows, and is interpreted as if it was "master". """ - if instance_name is None: instance_name = "master" @@ -660,33 +672,43 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore): async def get_room_events_stream_for_rooms( self, + *, room_ids: Collection[str], from_key: RoomStreamToken, - to_key: RoomStreamToken, + to_key: Optional[RoomStreamToken] = None, + direction: Direction = Direction.BACKWARDS, limit: int = 0, - order: str = "DESC", ) -> Dict[str, Tuple[List[EventBase], RoomStreamToken]]: """Get new room events in stream ordering since `from_key`. Args: room_ids - from_key: Token from which no events are returned before - to_key: Token from which no events are returned after. (This - is typically the current stream token) + from_key: The token to stream from (starting point and heading in the given + direction) + to_key: The token representing the end stream position (end point) limit: Maximum number of events to return - order: Either "DESC" or "ASC". Determines which events are - returned when the result is limited. If "DESC" then the most - recent `limit` events are returned, otherwise returns the - oldest `limit` events. + direction: Indicates whether we are paginating forwards or backwards + from `from_key`. Returns: A map from room id to a tuple containing: - list of recent events in the room - stream ordering key for the start of the chunk of events returned. + + When Direction.FORWARDS: from_key < x <= to_key, (ascending order) + When Direction.BACKWARDS: from_key >= x > to_key, (descending order) """ - room_ids = self._events_stream_cache.get_entities_changed( - room_ids, from_key.stream - ) + if direction == Direction.FORWARDS: + room_ids = self._events_stream_cache.get_entities_changed( + room_ids, from_key.stream + ) + elif direction == Direction.BACKWARDS: + if to_key is not None: + room_ids = self._events_stream_cache.get_entities_changed( + room_ids, to_key.stream + ) + else: + assert_never(direction) if not room_ids: return {} @@ -698,12 +720,12 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore): defer.gatherResults( [ run_in_background( - self.get_room_events_stream_for_room, - room_id, - from_key, - to_key, - limit, - order=order, + self.paginate_room_events_by_stream_ordering, + room_id=room_id, + from_key=from_key, + to_key=to_key, + direction=direction, + limit=limit, ) for room_id in rm_ids ], @@ -727,69 +749,122 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore): if self._events_stream_cache.has_entity_changed(room_id, from_id) } - async def get_room_events_stream_for_room( + async def paginate_room_events_by_stream_ordering( self, + *, room_id: str, from_key: RoomStreamToken, - to_key: RoomStreamToken, + to_key: Optional[RoomStreamToken] = None, + direction: Direction = Direction.BACKWARDS, limit: int = 0, - order: str = "DESC", ) -> Tuple[List[EventBase], RoomStreamToken]: - """Get new room events in stream ordering since `from_key`. + """ + Paginate events by `stream_ordering` in the room from the `from_key` in the + given `direction` to the `to_key` or `limit`. Args: room_id - from_key: Token from which no events are returned before - to_key: Token from which no events are returned after. (This - is typically the current stream token) + from_key: The token to stream from (starting point and heading in the given + direction) + to_key: The token representing the end stream position (end point) + direction: Indicates whether we are paginating forwards or backwards + from `from_key`. limit: Maximum number of events to return - order: Either "DESC" or "ASC". Determines which events are - returned when the result is limited. If "DESC" then the most - recent `limit` events are returned, otherwise returns the - oldest `limit` events. Returns: - The list of events (in ascending stream order) and the token from the start - of the chunk of events returned. + The results as a list of events and a token that points to the end + of the result set. If no events are returned then the end of the + stream has been reached (i.e. there are no events between `from_key` + and `to_key`). + + When Direction.FORWARDS: from_key < x <= to_key, (ascending order) + When Direction.BACKWARDS: from_key >= x > to_key, (descending order) """ - if from_key == to_key: - return [], from_key - has_changed = self._events_stream_cache.has_entity_changed( - room_id, from_key.stream - ) + # FIXME: When going forwards, we should enforce that the `to_key` is not `None` + # because we always need an upper bound when querying the events stream (as + # otherwise we'll potentially pick up events that are not fully persisted). + + # We should only be working with `stream_ordering` tokens here + assert from_key is None or from_key.topological is None + assert to_key is None or to_key.topological is None + + # We can bail early if we're looking forwards, and our `to_key` is already + # before our `from_key`. + if ( + direction == Direction.FORWARDS + and to_key is not None + and to_key.is_before_or_eq(from_key) + ): + # Token selection matches what we do below if there are no rows + return [], to_key if to_key else from_key + # Or vice-versa, if we're looking backwards and our `from_key` is already before + # our `to_key`. + elif ( + direction == Direction.BACKWARDS + and to_key is not None + and from_key.is_before_or_eq(to_key) + ): + # Token selection matches what we do below if there are no rows + return [], to_key if to_key else from_key + + # We can do a quick sanity check to see if any events have been sent in the room + # since the earlier token. + has_changed = True + if direction == Direction.FORWARDS: + has_changed = self._events_stream_cache.has_entity_changed( + room_id, from_key.stream + ) + elif direction == Direction.BACKWARDS: + if to_key is not None: + has_changed = self._events_stream_cache.has_entity_changed( + room_id, to_key.stream + ) + else: + assert_never(direction) if not has_changed: - return [], from_key + # Token selection matches what we do below if there are no rows + return [], to_key if to_key else from_key - def f(txn: LoggingTransaction) -> List[_EventDictReturn]: - # To handle tokens with a non-empty instance_map we fetch more - # results than necessary and then filter down - min_from_id = from_key.stream - max_to_id = to_key.get_max_stream_pos() + order, from_bound, to_bound = generate_pagination_bounds( + direction, from_key, to_key + ) - sql = """ - SELECT event_id, instance_name, topological_ordering, stream_ordering + bounds = generate_pagination_where_clause( + direction=direction, + # The empty string will shortcut downstream code to only use the + # `stream_ordering` column + column_names=("", "stream_ordering"), + from_token=from_bound, + to_token=to_bound, + engine=self.database_engine, + ) + + def f(txn: LoggingTransaction) -> List[_EventDictReturn]: + sql = f""" + SELECT event_id, instance_name, stream_ordering FROM events WHERE room_id = ? AND not outlier - AND stream_ordering > ? AND stream_ordering <= ? - ORDER BY stream_ordering %s LIMIT ? - """ % ( - order, - ) - txn.execute(sql, (room_id, min_from_id, max_to_id, 2 * limit)) + AND {bounds} + ORDER BY stream_ordering {order} LIMIT ? + """ + txn.execute(sql, (room_id, 2 * limit)) rows = [ _EventDictReturn(event_id, None, stream_ordering) - for event_id, instance_name, topological_ordering, stream_ordering in txn - if _filter_results( - from_key, - to_key, - instance_name, - topological_ordering, - stream_ordering, + for event_id, instance_name, stream_ordering in txn + if _filter_results_by_stream( + lower_token=( + to_key if direction == Direction.BACKWARDS else from_key + ), + upper_token=( + from_key if direction == Direction.BACKWARDS else to_key + ), + instance_name=instance_name, + stream_ordering=stream_ordering, ) ][:limit] return rows @@ -800,17 +875,18 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore): [r.event_id for r in rows], get_prev_content=True ) - if order.lower() == "desc": - ret.reverse() - if rows: - key = RoomStreamToken(stream=min(r.stream_ordering for r in rows)) + next_key = generate_next_token( + direction=direction, + last_topo_ordering=None, + last_stream_ordering=rows[-1].stream_ordering, + ) else: - # Assume we didn't get anything because there was nothing to - # get. - key = from_key + # TODO (erikj): We should work out what to do here instead. (same as + # `_paginate_room_events_by_topological_ordering_txn(...)`) + next_key = to_key if to_key else from_key - return ret, key + return ret, next_key @trace async def get_current_state_delta_membership_changes_for_user( @@ -1118,7 +1194,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore): rows, token = await self.db_pool.runInteraction( "get_recent_event_ids_for_room", - self._paginate_room_events_txn, + self._paginate_room_events_by_topological_ordering_txn, room_id, from_token=end_token, limit=limit, @@ -1624,7 +1700,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore): topological=topological_ordering, stream=stream_ordering ) - rows, start_token = self._paginate_room_events_txn( + rows, start_token = self._paginate_room_events_by_topological_ordering_txn( txn, room_id, before_token, @@ -1634,7 +1710,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore): ) events_before = [r.event_id for r in rows] - rows, end_token = self._paginate_room_events_txn( + rows, end_token = self._paginate_room_events_by_topological_ordering_txn( txn, room_id, after_token, @@ -1797,14 +1873,14 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore): def has_room_changed_since(self, room_id: str, stream_id: int) -> bool: return self._events_stream_cache.has_entity_changed(room_id, stream_id) - def _paginate_room_events_txn( + def _paginate_room_events_by_topological_ordering_txn( self, txn: LoggingTransaction, room_id: str, from_token: RoomStreamToken, to_token: Optional[RoomStreamToken] = None, direction: Direction = Direction.BACKWARDS, - limit: int = -1, + limit: int = 0, event_filter: Optional[Filter] = None, ) -> Tuple[List[_EventDictReturn], RoomStreamToken]: """Returns list of events before or after a given token. @@ -1826,6 +1902,24 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore): been reached (i.e. there are no events between `from_token` and `to_token`), or `limit` is zero. """ + # We can bail early if we're looking forwards, and our `to_key` is already + # before our `from_token`. + if ( + direction == Direction.FORWARDS + and to_token is not None + and to_token.is_before_or_eq(from_token) + ): + # Token selection matches what we do below if there are no rows + return [], to_token if to_token else from_token + # Or vice-versa, if we're looking backwards and our `from_token` is already before + # our `to_token`. + elif ( + direction == Direction.BACKWARDS + and to_token is not None + and from_token.is_before_or_eq(to_token) + ): + # Token selection matches what we do below if there are no rows + return [], to_token if to_token else from_token args: List[Any] = [room_id] @@ -1910,7 +2004,6 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore): "bounds": bounds, "order": order, } - txn.execute(sql, args) # Filter the result set. @@ -1943,27 +2036,29 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore): @trace @tag_args - async def paginate_room_events( + async def paginate_room_events_by_topological_ordering( self, + *, room_id: str, from_key: RoomStreamToken, to_key: Optional[RoomStreamToken] = None, direction: Direction = Direction.BACKWARDS, - limit: int = -1, + limit: int = 0, event_filter: Optional[Filter] = None, ) -> Tuple[List[EventBase], RoomStreamToken]: - """Returns list of events before or after a given token. - - When Direction.FORWARDS: from_key < x <= to_key - When Direction.BACKWARDS: from_key >= x > to_key + """ + Paginate events by `topological_ordering` (tie-break with `stream_ordering`) in + the room from the `from_key` in the given `direction` to the `to_key` or + `limit`. Args: room_id - from_key: The token used to stream from - to_key: A token which if given limits the results to only those before + from_key: The token to stream from (starting point and heading in the given + direction) + to_key: The token representing the end stream position (end point) direction: Indicates whether we are paginating forwards or backwards from `from_key`. - limit: The maximum number of events to return. + limit: Maximum number of events to return event_filter: If provided filters the events to those that match the filter. Returns: @@ -1971,8 +2066,18 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore): of the result set. If no events are returned then the end of the stream has been reached (i.e. there are no events between `from_key` and `to_key`). + + When Direction.FORWARDS: from_key < x <= to_key, (ascending order) + When Direction.BACKWARDS: from_key >= x > to_key, (descending order) """ + # FIXME: When going forwards, we should enforce that the `to_key` is not `None` + # because we always need an upper bound when querying the events stream (as + # otherwise we'll potentially pick up events that are not fully persisted). + + # We have these checks outside of the transaction function (txn) to save getting + # a DB connection and switching threads if we don't need to. + # # We can bail early if we're looking forwards, and our `to_key` is already # before our `from_key`. if ( @@ -1995,8 +2100,8 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore): return [], to_key if to_key else from_key rows, token = await self.db_pool.runInteraction( - "paginate_room_events", - self._paginate_room_events_txn, + "paginate_room_events_by_topological_ordering", + self._paginate_room_events_by_topological_ordering_txn, room_id, from_key, to_key, |