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From Damien Kamerman <>
Subject Re: backport Heliosearch features to Solr
Date Sun, 15 Mar 2015 08:48:08 GMT
Sounds like 64bit is OK. Would be work re-testing that G1GC assert trip
with the latest JDK.

On 14 March 2015 at 01:46, Shawn Heisey <> wrote:

> On 3/12/2015 5:11 PM, Markus Jelsma wrote:
> > Hello - i would assume off-heap would out perform any heap based data
> structure. G1 is only useful if you deal with very large heaps, and it eats
> CPU at the same time. As much as G1 is better than CMS in same cases, you
> would still have less wasted CPU time and resp. less STW events.
> >
> > Anyway. if someone has a setup at hand to provide details, please do :)
> I do not have any info about CPU usage with G1 vs. CMS.  My Solr servers
> are extremely lightly loaded so CPU usage is never a problem.  For very
> busy servers, that could be an issue, and CMS is probably the way to go.
> I have been able to reduce GC times (both the average time and the "long
> collection" time) by a large margin using G1 vs. CMS, with the help of
> the hotspot-gc-use mailing list maintained by the OpenJDK project.
> I keep my mad ramblings about GC tuning on the Solr wiki:
> The only caveat that I have is that the Lucene project has said never to
> use G1GC with Lucene.  Their exact words, found on the wiki URL below,
> are: "Do not, under any circumstances, run Lucene with the G1 garbage
> collector. "
> I can say that I have never had a problem with G1, but if you choose to
> use it, you should know that you are going against the advice of the
> people who write the code:
> Thanks,
> Shawn

Damien Kamerman

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