Roman, According to documentation [1] this setting is responsible for the amount of time to wait a lock to be released before trying to check if it is, in fact, a deadlock. This time just allows not to spend resources for unnecessary checks. If a lock is not a deadlock, this check will just skip it and request will continue to wait for a lock to be released until lock_timeout is exceeded.
[1] http://www.postgresql.org/docs/9.3/static/runtime-config-locks.html Vladimir Kozhukalov On Mon, Mar 21, 2016 at 7:39 PM, Roman Prykhodchenko <m...@romcheg.me> wrote: > Folks, > > We have been analyzing a bunch of random failures in Fuel tests and > encountered several ones caused by detector raising errors occasionally > [1]. After attempts to reproduce the same behavior have failed we’ve > decided to run the same test suit on overloaded nodes. Those test-runs > allowed us to catch the same behavior we’ve seen on CI slaves. After > analyzing both PostgreSQL logs and Nailgun’s code we’ve found no reasons > for those deadlocks to occur. > > Thinking about the facts mentioned we came up with the idea that those > random deadlocks occur in cases when CI slaves are overloaded by other jobs > and transactions start hitting deadlock timeout. Thus I propose to change > PostgreSQL’s deadlock_timeout value from the default one to 3-5 seconds. > That will slow down tests, if they run on an overloaded CI slave but will > help to avoid random and false-positive deadlock warnings. > > > References: > > 1. https://bugs.launchpad.net/fuel/+bug/1556070 > > > - romcheg > __________________________________________________________________________ > OpenStack Development Mailing List (not for usage questions) > Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >
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