On Wed, Feb 10, 2016 at 10:57 AM, James E. Blair <cor...@inaugust.com> wrote: > Michael Still <mi...@stillhq.com> writes: > >> On Tue, Feb 9, 2016 at 4:59 AM, Joshua Hesketh <joshua.hesk...@gmail.com> >> wrote: >> >>> On Thu, Feb 4, 2016 at 2:44 AM, James E. Blair <cor...@inaugust.com> >>> wrote: >>>> >>>> On the subject of clearing the cache more often, I think we may not want >>>> to wipe out the cache more often than we do now -- in fact, I think we >>>> may want to look into ways to keep from doing even that, because >>>> whenever we reload now, Zuul slows down considerably as it has to query >>>> Gerrit again for all of the data previously in its cache. >>>> >>> >>> I can see a lot of 3rd parties or simpler CI's not needing to reload zuul >>> very often so this cache would never get cleared. Perhaps cached objects >>> should have an expiry time (of a day or so) and can be cleaned up >>> periodically? Additionally if clearing the cache on a reload is causing >>> pain maybe we should move the cache into the scheduler and keep it between >>> reloads? >>> >> >> Do you guys use oslo at all? I ask because the olso memcache stuff does >> exactly this, so it should be trivial to implement if you don't mind >> depending on oslo. > > One of the main things we use the cache for is to ensure that every > change is represented by a single Change object in Zuul's memory. The > graph of enqueued Items link to their respective Changes which may link > to each other due to dependencies. When something changes in Gerrit, we > want that reflected immediately and consistently in all of the objects > in that graph. Using the cache means that every time we add a new > Change object to that graph, we use the same object for a given change. > > This is why we can't use time-based expiry -- we must not drop objects > from the cache if they are still in the graph. Otherwise we will create > new duplicative objects and the ones still in the graph will not be > updated. > > Perhaps we should change these objects to something more ephemeral that > can proxy for some other mechanism that can operate more like a > traditional cache (with time-based expiry). But I think changes to this > system should happen in Zuulv3 -- it works well enough for Zuulv2 for > now. > > -Jim >
We are one of third-party CIs and using "Zuul version: 2.1.1.dev123", which is one commit after [1]. That one commit after is not in tree - I am applying [2] on top. The VM has 8GB of RAM. zuul-server memory footprint goes up consistently over the course of a week. Normally it takes about 3-4 days to get over to 3Gb. About a week ago I witnessed zuul-server get to 95% of RAM, at which point kernel started killing other processes. The graph [3] memory [3], and it reflects zuul-server consumption. The daily bumps on the graph are daily cron doing log rotation etc, possibly flushing caches. I can not say 100% that it is still the leak. Could simply be that zuul-server requires more ram now. [1] https://review.openstack.org/#q,I81ee47524cda71a500c55a95a2280f491b1b63d9,n,z [2] https://review.openstack.org/#q,If3a418fa2d4993a149d454e02a9b26529e4b6825,n,z [3] http://imgur.com/SzqSA1H Mikhail Medvedev (mmedvede) _______________________________________________ OpenStack-Infra mailing list OpenStack-Infra@lists.openstack.org http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-infra