Hey Sebastian, As for how Solr/SolrJ compatibility is handled, the story for SolrJ looks a lot like the story for Solr itself - major version changes can introduce breaking changes, so it is best to avoid using SolrJ 6.x with Solr 7.x. In practice I think changes that break Solr/SolrJ compatibility are relatively rare though, so it might be possible if your hand is forced.
As for the behavior you described...I think I understand what you're describing, but to make sure: Are the "connection-evictor" threads accumulating in your client application, on the Solr server itself, or both? I suspect you're seeing this in your client code. If so, it'd really help us to help you if you could provide some more details on how you're using SolrJ. Can you share a small snippet (JUnit test?) that reproduces the problem? How are you creating the SolrClient you're using to send requests? Which SolrClient implementation(s) are you using? Are you providing your own HttpClient, or letting SolrClient create its own? It'll be much easier for others to help with a little more detail there. Best, Jason On Fri, Nov 23, 2018 at 10:38 AM Sebastian Riemer <s.rie...@littera.eu> wrote: > > Hi, > > we've recently changed our Solr-Version from 6.2.1 to 7.5.0, and since then, > whenever we execute a query on solr, a new thread is being created and never > closed. > > These threads are all labelled "Connection evictor" and the gather until a > critical mass is reached and either the OS cannot create anymore OS threads, > or an out of memory error is being produced. > > First I thought, that this might have as cause we were using a higher > SolrJ-Version than our Solr-Server (by mistakenly forgetting to uprade the > server version too): > > So we had for SolrJ: 7.4.0 > > <dependency> > <groupId>org.apache.solr</groupId> > <artifactId>solr-solrj</artifactId> > <version>7.4.0</version> > </dependency> > > And for Solr-Server: 6.2.1 > > But now I just installed the newest Solr-Server-Version 7.5.0 and still I see > with each Solr-Search performed an additional Thread being created and never > released. > > When downgrading SolrJ to 6.2.1 I can verify, that no new threads are created > when doing a solr search. > > What do you think about this? Are there any known pitfalls? Maybe I missed > some crucial changes necessary when upgrading to 7.5.0? > > What about differing versions in SolrJ and Solr-Server? As far as I recall > the docs, one major-version-difference up/down in both ways should be o.k. > > Thanks for all your feedback, > > Yours sincerely > > Sebastian Riemer
