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Simplify event persistence code (#16584) 

The event persistence code used to handle multiple rooms
at a time, but was simplified to only ever be called with a
single room at a time (different rooms are now handled in
parallel). The code is still generic to multiple rooms causing
a lot of work that is unnecessary (e.g. unnecessary loops, and
partitioning data by room).

This strips out the ability to handle multiple rooms at once, greatly
simplifying the code.
pull/16599/head
Patrick Cloke 2023-11-03 07:30:31 -04:00 committed by GitHub
parent 0afbef30cf
commit 92828a7f95
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4 changed files with 324 additions and 310 deletions
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1
changelog.d/16584.misc Normal file
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@ -0,0 +1 @@
Simplify persistance code to be per-room.

1
changelog.d/16586.misc Normal file
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@ -0,0 +1 @@
Avoid updating the stream cache unnecessarily.

98
synapse/storage/controllers/persist_events.py
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@ -542,13 +542,15 @@ class EventsPersistenceStorageController:
return await res.get_state(self._state_controller, StateFilter.all())
async def _persist_event_batch(
self, _room_id: str, task: _PersistEventsTask
self, room_id: str, task: _PersistEventsTask
) -> Dict[str, str]:
"""Callback for the _event_persist_queue
Calculates the change to current state and forward extremities, and
persists the given events and with those updates.
Assumes that we are only persisting events for one room at a time.
Returns:
A dictionary of event ID to event ID we didn't persist as we already
had another event persisted with the same TXN ID.
@ -594,41 +596,55 @@ class EventsPersistenceStorageController:
# We can't easily parallelize these since different chunks
# might contain the same event. :(
# NB: Assumes that we are only persisting events for one room
# at a time.
# map room_id->set[event_ids] giving the new forward
# extremities in each room
new_forward_extremities: Dict[str, Set[str]] = {}
# map room_id->(to_delete, to_insert) where to_delete is a list
# of type/state keys to remove from current state, and to_insert
# is a map (type,key)->event_id giving the state delta in each
# room
state_delta_for_room: Dict[str, DeltaState] = {}
new_forward_extremities = None
state_delta_for_room = None
if not backfilled:
with Measure(self._clock, "_calculate_state_and_extrem"):
# Work out the new "current state" for each room.
# Work out the new "current state" for the room.
# We do this by working out what the new extremities are and then
# calculating the state from that.
events_by_room: Dict[str, List[Tuple[EventBase, EventContext]]] = {}
for event, context in chunk:
events_by_room.setdefault(event.room_id, []).append(
(event, context)
(
new_forward_extremities,
state_delta_for_room,
) = await self._calculate_new_forward_extremities_and_state_delta(
room_id, chunk
)
for room_id, ev_ctx_rm in events_by_room.items():
latest_event_ids = (
await self.main_store.get_latest_event_ids_in_room(room_id)
await self.persist_events_store._persist_events_and_state_updates(
room_id,
chunk,
state_delta_for_room=state_delta_for_room,
new_forward_extremities=new_forward_extremities,
use_negative_stream_ordering=backfilled,
inhibit_local_membership_updates=backfilled,
)
return replaced_events
async def _calculate_new_forward_extremities_and_state_delta(
self, room_id: str, ev_ctx_rm: List[Tuple[EventBase, EventContext]]
) -> Tuple[Optional[Set[str]], Optional[DeltaState]]:
"""Calculates the new forward extremities and state delta for a room
given events to persist.
Assumes that we are only persisting events for one room at a time.
Returns:
A tuple of:
A set of str giving the new forward extremities the room
The state delta for the room.
"""
latest_event_ids = await self.main_store.get_latest_event_ids_in_room(room_id)
new_latest_event_ids = await self._calculate_new_extremities(
room_id, ev_ctx_rm, latest_event_ids
)
if new_latest_event_ids == latest_event_ids:
# No change in extremities, so no change in state
continue
return (None, None)
# there should always be at least one forward extremity.
# (except during the initial persistence of the send_join
@ -636,22 +652,18 @@ class EventsPersistenceStorageController:
# extremities, so we'll `continue` above and skip this bit.)
assert new_latest_event_ids, "No forward extremities left!"
new_forward_extremities[room_id] = new_latest_event_ids
new_forward_extremities = new_latest_event_ids
len_1 = (
len(latest_event_ids) == 1
and len(new_latest_event_ids) == 1
)
len_1 = len(latest_event_ids) == 1 and len(new_latest_event_ids) == 1
if len_1:
all_single_prev_not_state = all(
len(event.prev_event_ids()) == 1
and not event.is_state()
len(event.prev_event_ids()) == 1 and not event.is_state()
for event, ctx in ev_ctx_rm
)
# Don't bother calculating state if they're just
# a long chain of single ancestor non-state events.
if all_single_prev_not_state:
continue
return (new_forward_extremities, None)
state_delta_counter.inc()
if len(new_latest_event_ids) == 1:
@ -674,9 +686,7 @@ class EventsPersistenceStorageController:
break
logger.debug("Calculating state delta for room %s", room_id)
with Measure(
self._clock, "persist_events.get_new_state_after_events"
):
with Measure(self._clock, "persist_events.get_new_state_after_events"):
res = await self._get_new_state_after_events(
room_id,
ev_ctx_rm,
@ -691,7 +701,7 @@ class EventsPersistenceStorageController:
# extremities, so we'll `continue` above and skip this bit.)
assert new_latest_event_ids, "No forward extremities left!"
new_forward_extremities[room_id] = new_latest_event_ids
new_forward_extremities = new_latest_event_ids
# If either are not None then there has been a change,
# and we need to work out the delta (or use that
@ -703,12 +713,8 @@ class EventsPersistenceStorageController:
# removed keys entirely.
delta = DeltaState([], delta_ids)
elif current_state is not None:
with Measure(
self._clock, "persist_events.calculate_state_delta"
):
delta = await self._calculate_state_delta(
room_id, current_state
)
with Measure(self._clock, "persist_events.calculate_state_delta"):
delta = await self._calculate_state_delta(room_id, current_state)
if delta:
# If we have a change of state then lets check
@ -725,17 +731,7 @@ class EventsPersistenceStorageController:
logger.info("Server no longer in room %s", room_id)
delta.no_longer_in_room = True
state_delta_for_room[room_id] = delta
await self.persist_events_store._persist_events_and_state_updates(
chunk,
state_delta_for_room=state_delta_for_room,
new_forward_extremities=new_forward_extremities,
use_negative_stream_ordering=backfilled,
inhibit_local_membership_updates=backfilled,
)
return replaced_events
return (new_forward_extremities, delta)
async def _calculate_new_extremities(
self,

110
synapse/storage/databases/main/events.py
View File

@ -79,7 +79,7 @@ class DeltaState:
Attributes:
to_delete: List of type/state_keys to delete from current state
to_insert: Map of state to upsert into current state
no_longer_in_room: The server is not longer in the room, so the room
no_longer_in_room: The server is no longer in the room, so the room
should e.g. be removed from `current_state_events` table.
"""
@ -131,22 +131,25 @@ class PersistEventsStore:
@trace
async def _persist_events_and_state_updates(
self,
room_id: str,
events_and_contexts: List[Tuple[EventBase, EventContext]],
*,
state_delta_for_room: Dict[str, DeltaState],
new_forward_extremities: Dict[str, Set[str]],
state_delta_for_room: Optional[DeltaState],
new_forward_extremities: Optional[Set[str]],
use_negative_stream_ordering: bool = False,
inhibit_local_membership_updates: bool = False,
) -> None:
"""Persist a set of events alongside updates to the current state and
forward extremities tables.
Assumes that we are only persisting events for one room at a time.
Args:
room_id:
events_and_contexts:
state_delta_for_room: Map from room_id to the delta to apply to
room state
new_forward_extremities: Map from room_id to set of event IDs
that are the new forward extremities of the room.
state_delta_for_room: The delta to apply to the room state
new_forward_extremities: A set of event IDs that are the new forward
extremities of the room.
use_negative_stream_ordering: Whether to start stream_ordering on
the negative side and decrement. This should be set as True
for backfilled events because backfilled events get a negative
@ -196,6 +199,7 @@ class PersistEventsStore:
await self.db_pool.runInteraction(
"persist_events",
self._persist_events_txn,
room_id=room_id,
events_and_contexts=events_and_contexts,
inhibit_local_membership_updates=inhibit_local_membership_updates,
state_delta_for_room=state_delta_for_room,
@ -221,9 +225,9 @@ class PersistEventsStore:
event_counter.labels(event.type, origin_type, origin_entity).inc()
for room_id, latest_event_ids in new_forward_extremities.items():
if new_forward_extremities:
self.store.get_latest_event_ids_in_room.prefill(
(room_id,), frozenset(latest_event_ids)
(room_id,), frozenset(new_forward_extremities)
)
async def _get_events_which_are_prevs(self, event_ids: Iterable[str]) -> List[str]:
@ -336,10 +340,11 @@ class PersistEventsStore:
self,
txn: LoggingTransaction,
*,
room_id: str,
events_and_contexts: List[Tuple[EventBase, EventContext]],
inhibit_local_membership_updates: bool,
state_delta_for_room: Dict[str, DeltaState],
new_forward_extremities: Dict[str, Set[str]],
state_delta_for_room: Optional[DeltaState],
new_forward_extremities: Optional[Set[str]],
) -> None:
"""Insert some number of room events into the necessary database tables.
@ -347,8 +352,11 @@ class PersistEventsStore:
and the rejections table. Things reading from those table will need to check
whether the event was rejected.
Assumes that we are only persisting events for one room at a time.
Args:
txn
room_id: The room the events are from
events_and_contexts: events to persist
inhibit_local_membership_updates: Stop the local_current_membership
from being updated by these events. This should be set to True
@ -357,10 +365,9 @@ class PersistEventsStore:
delete_existing True to purge existing table rows for the events
from the database. This is useful when retrying due to
IntegrityError.
state_delta_for_room: The current-state delta for each room.
new_forward_extremities: The new forward extremities for each room.
For each room, a list of the event ids which are the forward
extremities.
state_delta_for_room: The current-state delta for the room.
new_forward_extremities: The new forward extremities for the room:
a set of the event ids which are the forward extremities.
Raises:
PartialStateConflictError: if attempting to persist a partial state event in
@ -376,7 +383,6 @@ class PersistEventsStore:
#
# Annoyingly SQLite doesn't support row level locking.
if isinstance(self.database_engine, PostgresEngine):
for room_id in {e.room_id for e, _ in events_and_contexts}:
txn.execute(
"SELECT room_version FROM rooms WHERE room_id = ? FOR SHARE",
(room_id,),
@ -419,7 +425,9 @@ class PersistEventsStore:
events_and_contexts
)
self._update_room_depths_txn(txn, events_and_contexts=events_and_contexts)
self._update_room_depths_txn(
txn, room_id, events_and_contexts=events_and_contexts
)
# _update_outliers_txn filters out any events which have already been
# persisted, and returns the filtered list.
@ -432,8 +440,10 @@ class PersistEventsStore:
self._store_event_txn(txn, events_and_contexts=events_and_contexts)
if new_forward_extremities:
self._update_forward_extremities_txn(
txn,
room_id,
new_forward_extremities=new_forward_extremities,
max_stream_order=max_stream_order,
)
@ -464,7 +474,10 @@ class PersistEventsStore:
# We call this last as it assumes we've inserted the events into
# room_memberships, where applicable.
# NB: This function invalidates all state related caches
self._update_current_state_txn(txn, state_delta_for_room, min_stream_order)
if state_delta_for_room:
self._update_current_state_txn(
txn, room_id, state_delta_for_room, min_stream_order
)
def _persist_event_auth_chain_txn(
self,
@ -1026,17 +1039,18 @@ class PersistEventsStore:
await self.db_pool.runInteraction(
"update_current_state",
self._update_current_state_txn,
state_delta_by_room={room_id: state_delta},
room_id,
delta_state=state_delta,
stream_id=stream_ordering,
)
def _update_current_state_txn(
self,
txn: LoggingTransaction,
state_delta_by_room: Dict[str, DeltaState],
room_id: str,
delta_state: DeltaState,
stream_id: int,
) -> None:
for room_id, delta_state in state_delta_by_room.items():
to_delete = delta_state.to_delete
to_insert = delta_state.to_insert
@ -1190,9 +1204,7 @@ class PersistEventsStore:
)
# Invalidate the various caches
self.store._invalidate_state_caches_and_stream(
txn, room_id, members_changed
)
self.store._invalidate_state_caches_and_stream(txn, room_id, members_changed)
# Check if any of the remote membership changes requires us to
# unsubscribe from their device lists.
@ -1232,10 +1244,10 @@ class PersistEventsStore:
def _update_forward_extremities_txn(
self,
txn: LoggingTransaction,
new_forward_extremities: Dict[str, Set[str]],
room_id: str,
new_forward_extremities: Set[str],
max_stream_order: int,
) -> None:
for room_id in new_forward_extremities.keys():
self.db_pool.simple_delete_txn(
txn, table="event_forward_extremities", keyvalues={"room_id": room_id}
)
@ -1244,11 +1256,7 @@ class PersistEventsStore:
txn,
table="event_forward_extremities",
keys=("event_id", "room_id"),
values=[
(ev_id, room_id)
for room_id, new_extrem in new_forward_extremities.items()
for ev_id in new_extrem
],
values=[(ev_id, room_id) for ev_id in new_forward_extremities],
)
# We now insert into stream_ordering_to_exterm a mapping from room_id,
# new stream_ordering to new forward extremeties in the room.
@ -1260,8 +1268,7 @@ class PersistEventsStore:
keys=("room_id", "event_id", "stream_ordering"),
values=[
(room_id, event_id, max_stream_order)
for room_id, new_extrem in new_forward_extremities.items()
for event_id in new_extrem
for event_id in new_forward_extremities
],
)
@ -1298,36 +1305,45 @@ class PersistEventsStore:
def _update_room_depths_txn(
self,
txn: LoggingTransaction,
room_id: str,
events_and_contexts: List[Tuple[EventBase, EventContext]],
) -> None:
"""Update min_depth for each room
Args:
txn: db connection
room_id: The room ID
events_and_contexts: events we are persisting
"""
depth_updates: Dict[str, int] = {}
stream_ordering: Optional[int] = None
depth_update = 0
for event, context in events_and_contexts:
# Then update the `stream_ordering` position to mark the latest
# event as the front of the room. This should not be done for
# backfilled events because backfilled events have negative
# stream_ordering and happened in the past so we know that we don't
# need to update the stream_ordering tip/front for the room.
# Don't update the stream ordering for backfilled events because
# backfilled events have negative stream_ordering and happened in the
# past, so we know that we don't need to update the stream_ordering
# tip/front for the room.
assert event.internal_metadata.stream_ordering is not None
if event.internal_metadata.stream_ordering >= 0:
txn.call_after(
self.store._events_stream_cache.entity_has_changed,
event.room_id,
event.internal_metadata.stream_ordering,
if stream_ordering is None:
stream_ordering = event.internal_metadata.stream_ordering
else:
stream_ordering = max(
stream_ordering, event.internal_metadata.stream_ordering
)
if not event.internal_metadata.is_outlier() and not context.rejected:
depth_updates[event.room_id] = max(
event.depth, depth_updates.get(event.room_id, event.depth)
depth_update = max(event.depth, depth_update)
# Then update the `stream_ordering` position to mark the latest event as
# the front of the room.
if stream_ordering is not None:
txn.call_after(
self.store._events_stream_cache.entity_has_changed,
room_id,
stream_ordering,
)
for room_id, depth in depth_updates.items():
self._update_min_depth_for_room_txn(txn, room_id, depth)
self._update_min_depth_for_room_txn(txn, room_id, depth_update)
def _update_outliers_txn(
self,