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List:       solr-user
Subject:    Re: Out of memory on some faceting queries
From:       Dotan Cohen <dotancohen () gmail ! com>
Date:       2013-04-08 7:16:58
Message-ID: CAKDXFkMKibxh6WW+-uThqiLXnjFaL1KAuhpRCQmemiaN1OPcSA () mail ! gmail ! com
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On Wed, Apr 3, 2013 at 8:47 PM, Shawn Heisey <solr@elyograg.org> wrote:
> On 4/2/2013 3:09 AM, Dotan Cohen wrote:
>> I notice that this only occurs on queries that run facets. I start
>> Solr with the following command:
>> sudo nohup java -XX:NewRatio=1 -XX:+UseParNewGC
>> -XX:+UseConcMarkSweepGC -XX:+CMSParallelRemarkEnabled
>> -Dsolr.solr.home=/mnt/SolrFiles100/solr -jar
>> /opt/solr-4.1.0/example/start.jar &
>
> It looks like you've followed some advice that I gave previously on how
> to tune java.  I have since learned that this advice is bad, it results
> in long GC pauses, even with heaps that aren't huge.
>

I see, thanks.

> As others have pointed out, you don't have a max heap setting, which
> would mean that you're using whatever Java chooses for its default,
> which might not be enough.  If you can get Solr to successfully run for
> a while with queries and updates happening, the heap should eventually
> max out and the admin UI will show you what Java is choosing by default.
>
> Here is what I would now recommend for a beginning point on your Solr
> startup command.  You may need to increase the heap beyond 4GB, but be
> careful that you still have enough free memory to be able to do
> effective caching of your index.
>
> sudo nohup java -Xms4096M -Xmx4096M -XX:+UseConcMarkSweepGC
> -XX:CMSInitiatingOccupancyFraction=75 -XX:NewRatio=3
> -XX:MaxTenuringThreshold=8 -XX:+CMSParallelRemarkEnabled
> -XX:+ParallelRefProcEnabled -XX:+UseLargePages -XX:+AggressiveOpts
> -Dsolr.solr.home=/mnt/SolrFiles100/solr -jar
> /opt/solr-4.1.0/example/start.jar &
>

Thank you, I will experiment with that.

> If you are running a really old build of java (latest versions on
> Oracle's website are 1.6 build 43 and 1.7 build 17), you might want to
> leave AggressiveOpts out.  Some people would argue that you should never
> use that option.
>

Great, thank for the warning. This is what we're running, I'll see
about updating it through my distro's package manager:
$ java -version
java version "1.6.0_27"
OpenJDK Runtime Environment (IcedTea6 1.12.3) (6b27-1.12.3-0ubuntu1~12.04.1)
OpenJDK 64-Bit Server VM (build 20.0-b12, mixed mode)

--
Dotan Cohen

http://gibberish.co.il
http://what-is-what.com
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