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https://issues.apache.org/jira/browse/SOLR-7319?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14388154#comment-14388154
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Ferenczi Jim commented on SOLR-7319:
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Most of the java options in the solr.in.cmd should not be activated by default.
The tenuring threshold, the numbers of threads for the GC, ..., they all depend
on the type of deployment you have, the size of the heap and the machine
hosting the Solr node. In my company we are using a custom script full of java
options that we added over the years. Most of the options are here because
somebody added this with the assertion that the performance are better. Most of
the time, we don't know what the option is for but nobody wants to remove it
because the urban legend says it's useful. The solr startup script should be
almost empty (at least for the java options), maybe one or two options to set
up the garbage collector and that's it.
> Workaround the "Four Month Bug" causing GC pause problems
> ---------------------------------------------------------
>
> Key: SOLR-7319
> URL: https://issues.apache.org/jira/browse/SOLR-7319
> Project: Solr
> Issue Type: Bug
> Components: scripts and tools
> Affects Versions: 5.0
> Reporter: Shawn Heisey
> Assignee: Shawn Heisey
> Fix For: 5.1
>
> Attachments: SOLR-7319.patch, SOLR-7319.patch, SOLR-7319.patch
>
>
> A twitter engineer found a bug in the JVM that contributes to GC pause
> problems:
> http://www.evanjones.ca/jvm-mmap-pause.html
> Problem summary (in case the blog post disappears): The JVM calculates
> statistics on things like garbage collection and writes them to a file in the
> temp directory using MMAP. If there is a lot of other MMAP write activity,
> which is precisely how Lucene accomplishes indexing and merging, it can
> result in a GC pause because the mmap write to the temp file is delayed.
> We should implement the workaround in the solr start scripts (disable
> creation of the mmap statistics tempfile) and document the impact in
> CHANGES.txt.
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