Reduce spurious calls to generate sync

pull/2002/head
Erik Johnston 2017-03-14 15:03:46 +00:00
parent 6a3c5d6891
commit fd2eef49c8
1 changed files with 31 additions and 13 deletions

View File

@ -73,6 +73,13 @@ class _NotifierUserStream(object):
self.user_id = user_id
self.rooms = set(rooms)
self.current_token = current_token
# The last token for which we should wake up any streams that have a
# token that comes before it. This gets updated everytime we get poked.
# We start it at the current token since if we get any streams
# that have a token from before we have no idea whether they should be
# woken up or not, so lets just wake them up.
self.last_notified_token = current_token
self.last_notified_ms = time_now_ms
with PreserveLoggingContext():
@ -89,6 +96,7 @@ class _NotifierUserStream(object):
self.current_token = self.current_token.copy_and_advance(
stream_key, stream_id
)
self.last_notified_token = self.current_token
self.last_notified_ms = time_now_ms
noify_deferred = self.notify_deferred
@ -113,8 +121,14 @@ class _NotifierUserStream(object):
def new_listener(self, token):
"""Returns a deferred that is resolved when there is a new token
greater than the given token.
Args:
token: The token from which we are streaming from, i.e. we shouldn't
notify for things that happened before this.
"""
if self.current_token.is_after(token):
# Immediately wake up stream if something has already since happened
# since their last token.
if self.last_notified_token.is_after(token):
return _NotificationListener(defer.succeed(self.current_token))
else:
return _NotificationListener(self.notify_deferred.observe())
@ -294,40 +308,44 @@ class Notifier(object):
self._register_with_keys(user_stream)
result = None
prev_token = from_token
if timeout:
end_time = self.clock.time_msec() + timeout
prev_token = from_token
while not result:
try:
current_token = user_stream.current_token
result = yield callback(prev_token, current_token)
if result:
break
now = self.clock.time_msec()
if end_time <= now:
break
# Now we wait for the _NotifierUserStream to be told there
# is a new token.
# We need to supply the token we supplied to callback so
# that we don't miss any current_token updates.
prev_token = current_token
listener = user_stream.new_listener(prev_token)
with PreserveLoggingContext():
yield self.clock.time_bound_deferred(
listener.deferred,
time_out=(end_time - now) / 1000.
)
current_token = user_stream.current_token
result = yield callback(prev_token, current_token)
if result:
break
# Update the prev_token to the current_token since nothing
# has happened between the old prev_token and the current_token
prev_token = current_token
except DeferredTimedOutError:
break
except defer.CancelledError:
break
else:
if result is None:
# This happened if there was no timeout or if the timeout had
# already expired.
current_token = user_stream.current_token
result = yield callback(from_token, current_token)
result = yield callback(prev_token, current_token)
defer.returnValue(result)