Remove fallback from get_missing_events.

get_missing_events used to fallback to fetching the missing events
individually requesting from every server in the room, one by one.e

This could be unacceptably slow, possibly causing #1732
This commit is contained in:
Mark Haines 2016-12-30 18:13:15 +00:00
parent 0eac4fa525
commit cc50b1ae53

View file

@ -27,7 +27,6 @@ from synapse.util.caches.expiringcache import ExpiringCache
from synapse.util.logutils import log_function
from synapse.util.logcontext import preserve_fn, preserve_context_over_deferred
from synapse.events import FrozenEvent
from synapse.types import get_domain_from_id
import synapse.metrics
from synapse.util.retryutils import get_retry_limiter, NotRetryingDestination
@ -741,8 +740,6 @@ class FederationClient(FederationBase):
signed_events = yield self._check_sigs_and_hash_and_fetch(
destination, events, outlier=False
)
have_gotten_all_from_destination = True
except HttpResponseException as e:
if not e.code == 400:
raise
@ -750,72 +747,6 @@ class FederationClient(FederationBase):
# We are probably hitting an old server that doesn't support
# get_missing_events
signed_events = []
have_gotten_all_from_destination = False
if len(signed_events) >= limit:
defer.returnValue(signed_events)
users = yield self.state.get_current_user_in_room(room_id)
servers = set(get_domain_from_id(u) for u in users)
servers = set(servers)
servers.discard(self.server_name)
failed_to_fetch = set()
while len(signed_events) < limit:
# Are we missing any?
seen_events = set(earliest_events_ids)
seen_events.update(e.event_id for e in signed_events if e)
missing_events = {}
for e in itertools.chain(latest_events, signed_events):
if e.depth > min_depth:
missing_events.update({
e_id: e.depth for e_id, _ in e.prev_events
if e_id not in seen_events
and e_id not in failed_to_fetch
})
if not missing_events:
break
have_seen = yield self.store.have_events(missing_events)
for k in have_seen:
missing_events.pop(k, None)
if not missing_events:
break
# Okay, we haven't gotten everything yet. Lets get them.
ordered_missing = sorted(missing_events.items(), key=lambda x: x[0])
if have_gotten_all_from_destination:
servers.discard(destination)
def random_server_list():
srvs = list(servers)
random.shuffle(srvs)
return srvs
deferreds = [
preserve_fn(self.get_pdu)(
destinations=random_server_list(),
event_id=e_id,
)
for e_id, depth in ordered_missing[:limit - len(signed_events)]
]
res = yield preserve_context_over_deferred(
defer.DeferredList(deferreds, consumeErrors=True)
)
for (result, val), (e_id, _) in zip(res, ordered_missing):
if result and val:
signed_events.append(val)
else:
failed_to_fetch.add(e_id)
defer.returnValue(signed_events)