We have a fix for this issue, if I recall. The version is 8.6 but the problem likely existed long before -- there's been little improvements that I've seen to deep SolrCloud internals in recent years.
~ David Smiley Apache Lucene/Solr Search Developer http://www.linkedin.com/in/davidwsmiley On Thu, May 18, 2023 at 11:49 PM Gus Heck <gus.h...@gmail.com> wrote: > What version of solr is having this problem? > > On Tue, Mar 28, 2023 at 10:47 AM Pierre Salagnac < > pierre.salag...@gmail.com> > wrote: > > > Hello everyone, > > I'm investigating issues where a replica ends in having no leader, and I > > wonder whether my specified cases were already discussed somewhere. > > > > More specifically in the code, I (with the help of my colleagues) > > identified two gaps where we exit the leadership process, without going > > back to it ever. Both of them happen when the election ephemeral node is > > dropped because the Zookeeper session expired. > > > > First one, in class LeaderElector: > > - we log *"Our node is no longer in line to be leader"* > > - and immediately return > > > > Second one, in class > > * - we log "Will not register as leader because it seems the election is > no > > longer taking place."* > > - and immediately return > > > > For both cases, we explicitly check our sequential node still exists in > the > > election. First case has a call to zkClient.getChildren(...) and we then > > validate the results, while the second case catches a NoNodeException. > > If I don't miss anything, the node won't get back to this election. Since > > we aborted, this allows other eventual nodes to be the leader for this > > shard. But if they're not there (and we are), we just can't be the > leader. > > > > > > Taking a step back, it seems to me error handling in the leader election > > code is messy. There are a large number of catch blocks. Some of them > > trigger a retry of the election while some of them don't. > > > > Are they issues that were already discussed ? > > Thanks > > > > > -- > http://www.needhamsoftware.com (work) > http://www.the111shift.com (play) >
