From 130df8fb01bce1bf244940131d85d1c1a54ed5ef Mon Sep 17 00:00:00 2001 From: Erik Johnston Date: Fri, 6 Mar 2015 10:25:36 +0000 Subject: [PATCH] Add some randomness to the user specified timeout on event streams to mitigate against thundering herds problems --- synapse/handlers/events.py | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/synapse/handlers/events.py b/synapse/handlers/events.py index 8d5f5c849..d3297b729 100644 --- a/synapse/handlers/events.py +++ b/synapse/handlers/events.py @@ -23,6 +23,7 @@ from synapse.events.utils import serialize_event from ._base import BaseHandler import logging +import random logger = logging.getLogger(__name__) @@ -72,6 +73,14 @@ class EventStreamHandler(BaseHandler): rm_handler = self.hs.get_handlers().room_member_handler room_ids = yield rm_handler.get_rooms_for_user(auth_user) + if timeout: + # If they've set a timeout set a minimum limit. + timeout = max(timeout, 500) + + # Add some randomness to this value to try and mitigate against + # thundering herds on restart. + timeout = random.randint(int(timeout*0.9), int(timeout*1.1)) + with PreserveLoggingContext(): events, tokens = yield self.notifier.get_events_for( auth_user, room_ids, pagin_config, timeout