Fix incorrect truncation in get_missing_events

It's quite important that get_missing_events returns the *latest* events in the
room; however we were pulling event ids out of the database until we got *at
least* 10, and then taking the *earliest* of the results.

We also shouldn't really be relying on depth, and should be checking the
room_id.
This commit is contained in:
Richard van der Hoff 2018-10-16 20:37:16 +01:00
parent b8a5b0097c
commit fc0f13dd03
5 changed files with 26 additions and 35 deletions

1
changelog.d/4045.bugfix Normal file
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@ -0,0 +1 @@
Fix bug which made get_missing_events return too few events

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@ -507,19 +507,19 @@ class FederationServer(FederationBase):
@defer.inlineCallbacks
@log_function
def on_get_missing_events(self, origin, room_id, earliest_events,
latest_events, limit, min_depth):
latest_events, limit):
with (yield self._server_linearizer.queue((origin, room_id))):
origin_host, _ = parse_server_name(origin)
yield self.check_server_matches_acl(origin_host, room_id)
logger.info(
"on_get_missing_events: earliest_events: %r, latest_events: %r,"
" limit: %d, min_depth: %d",
earliest_events, latest_events, limit, min_depth
" limit: %d",
earliest_events, latest_events, limit,
)
missing_events = yield self.handler.on_get_missing_events(
origin, room_id, earliest_events, latest_events, limit, min_depth
origin, room_id, earliest_events, latest_events, limit,
)
if len(missing_events) < 5:

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@ -560,7 +560,6 @@ class FederationGetMissingEventsServlet(BaseFederationServlet):
@defer.inlineCallbacks
def on_POST(self, origin, content, query, room_id):
limit = int(content.get("limit", 10))
min_depth = int(content.get("min_depth", 0))
earliest_events = content.get("earliest_events", [])
latest_events = content.get("latest_events", [])
@ -569,7 +568,6 @@ class FederationGetMissingEventsServlet(BaseFederationServlet):
room_id=room_id,
earliest_events=earliest_events,
latest_events=latest_events,
min_depth=min_depth,
limit=limit,
)

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@ -309,8 +309,8 @@ class FederationHandler(BaseHandler):
if sent_to_us_directly:
logger.warn(
"[%s %s] Failed to fetch %d prev events: rejecting",
room_id, event_id, len(prevs - seen),
"[%s %s] Rejecting: failed to fetch %d prev events: %s",
room_id, event_id, len(prevs - seen), shortstr(prevs - seen)
)
raise FederationError(
"ERROR",
@ -452,8 +452,8 @@ class FederationHandler(BaseHandler):
latest |= seen
logger.info(
"[%s %s]: Requesting %d prev_events: %s",
room_id, event_id, len(prevs - seen), shortstr(prevs - seen)
"[%s %s]: Requesting missing events between %s and %s",
room_id, event_id, shortstr(latest), event_id,
)
# XXX: we set timeout to 10s to help workaround
@ -1852,7 +1852,7 @@ class FederationHandler(BaseHandler):
@defer.inlineCallbacks
def on_get_missing_events(self, origin, room_id, earliest_events,
latest_events, limit, min_depth):
latest_events, limit):
in_room = yield self.auth.check_host_in_room(
room_id,
origin
@ -1861,14 +1861,12 @@ class FederationHandler(BaseHandler):
raise AuthError(403, "Host not in room.")
limit = min(limit, 20)
min_depth = max(min_depth, 0)
missing_events = yield self.store.get_missing_events(
room_id=room_id,
earliest_events=earliest_events,
latest_events=latest_events,
limit=limit,
min_depth=min_depth,
)
missing_events = yield filter_events_for_server(

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@ -376,33 +376,25 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore,
@defer.inlineCallbacks
def get_missing_events(self, room_id, earliest_events, latest_events,
limit, min_depth):
limit):
ids = yield self.runInteraction(
"get_missing_events",
self._get_missing_events,
room_id, earliest_events, latest_events, limit, min_depth
room_id, earliest_events, latest_events, limit,
)
events = yield self._get_events(ids)
events = sorted(
[ev for ev in events if ev.depth >= min_depth],
key=lambda e: e.depth,
)
defer.returnValue(events[:limit])
defer.returnValue(events)
def _get_missing_events(self, txn, room_id, earliest_events, latest_events,
limit, min_depth):
limit):
earliest_events = set(earliest_events)
front = set(latest_events) - earliest_events
event_results = set()
seen_events = set(earliest_events)
front = set(latest_events) - seen_events
event_results = []
query = (
"SELECT prev_event_id FROM event_edges "
"WHERE event_id = ? AND is_state = ? "
"WHERE room_id = ? AND event_id = ? AND is_state = ? "
"LIMIT ?"
)
@ -411,18 +403,20 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore,
for event_id in front:
txn.execute(
query,
(event_id, False, limit - len(event_results))
(room_id, event_id, False, limit - len(event_results))
)
for e_id, in txn:
new_front.add(e_id)
new_results = set(t[0] for t in txn) - seen_events
new_front -= earliest_events
new_front -= event_results
new_front |= new_results
seen_events |= new_results
event_results.extend(new_results)
front = new_front
event_results |= new_front
# we built the list working backwards from latest_events; we now need to
# reverse it so that the events are approximately chronological.
event_results.reverse()
return event_results