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From Modassar Ather <modather1...@gmail.com>
Subject Re: Query time out. Solr node goes down.
Date Tue, 18 Aug 2015 05:08:09 GMT
Shawn! The container I am using is jetty only and the JVM setting I am
using is the default one which comes with Solr startup scripts. Yes I have
changed the JVM memory setting as mentioned.
Kindly help me understand, even if there is a a GC pause why the solr node
will go down. At least for other queries is should not throw exception of
*org.apache.solr.common.SolrException: no servers hosting shard.*
Why the node will throw above exception even a huge query is time out or
may have taken lot of resources. Kindly help me understand in what
conditions such exception can arise as I am not fully aware of it.

Daniel! The error logs do not say if it was JVM crash or just solr. But by
the exception I understand that it might have gone to a state from where it
recovered after sometime. I did not restart the Solr.

On Mon, Aug 17, 2015 at 10:12 PM, Daniel Collins <danwcollins@gmail.com>
wrote:

> When you say "the solr node goes down", what do you mean by that? From your
> comment on the logs, you obviously lose the solr core at best (you do
> realize only having a single replica is inherently susceptible to failure,
> right?)
> But do you mean the Solr Core drops out of the collection (ZK timeout), the
> JVM stops, the whole machine crashes?
>
> On 17 August 2015 at 14:17, Shawn Heisey <apache@elyograg.org> wrote:
>
> > On 8/17/2015 5:45 AM, Modassar Ather wrote:
> > > The servers have 32g memory each. Solr JVM memory is set to -Xms20g
> > > -Xmx24g. There are no OOM in logs.
> >
> > Are you starting Solr 5.2.1 with the included start script, or have you
> > installed it into another container?
> >
> > Assuming you're using the download's "bin/solr" script, that will
> > normally set Xms and Xmx to the same value, so if you have overridden
> > the memory settings such that you can have different values in Xms and
> > Xmx, have you also overridden the garbage collection parameters?  If you
> > have, what are they set to now?  You can see all arguments used on
> > startup in the "JVM" section of the admin UI dashboard.
> >
> > If you've installed in an entirely different container, or you have
> > overridden the garbage collection settings, then a 24GB heap might have
> > extreme garbage collection pauses, lasting long enough to exceed the
> > timeout.
> >
> > Giving 24 out of 32GB to Solr will mean that there is only (at most) 8GB
> > left over for caching the index.  With 200GB of index, this is nowhere
> > near enough, and is another likely source of Solr performance problems
> > that cause timeouts.  This is what Upayavira was referring to in his
> > reply.  For good performance with 200GB of index, you may need a lot
> > more than 32GB of total RAM.
> >
> > https://wiki.apache.org/solr/SolrPerformanceProblems
> >
> > This wiki page also describes how you can use jconsole to judge how much
> > heap you actually need.  24GB may be too much.
> >
> > Thanks,
> > Shawn
> >
> >
>

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