[jira] [Comment Edited] (CASSANDRA-10140) Enable GC logging by default

["Ariel Weisberg (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-10140?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14705573#comment-14705573 ] 

Ariel Weisberg edited comment on CASSANDRA-10140 at 8/20/15 7:28 PM:
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Trying to establish the impact empirically is not going to be easy. If you turn on gc logging and run cstar I would not expect to see an impact.

This something that happens pretty rarely even on configurations that suffer from it. You really do have to get unlucky. So maybe it doesn't matter. Pauses occur out the yin yang anyways so the benefit of having GC logging will easily outweigh the occasional hiccup.

I am just socializing the concern not -1ing it.

We did go to the trouble of disabling one other source of this kind of infrequent [JVM writes to the filesystem blocking the VM already.|https://issues.apache.org/jira/browse/CASSANDRA-9242] This would be a step in the opposite direction IF the JVM doesn't do the logging correctly.


was (Author: aweisberg):
Trying to establish the impact empirically is not going to be easy. If you turn on gc logging and run cstar I would not expect to see an impact.

The is something that happens pretty rarely even on configurations that suffer from it. You really do have to get unlucky. So maybe it doesn't matter. Pauses occur out the yin yang anyways so the benefit of having GC logging will easily outweigh the occasional hiccup.

I am just socializing the concern not -1ing it.

We did go to the trouble of disabling one other source of this kind of infrequent [JVM writes to the filesystem blocking the VM already.|https://issues.apache.org/jira/browse/CASSANDRA-9242] This would be a step in the opposite direction IF the JVM doesn't do the logging correctly.

> Enable GC logging by default
> ----------------------------
>
>                 Key: CASSANDRA-10140
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-10140
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Config
>            Reporter: Chris Lohfink
>            Assignee: Chris Lohfink
>            Priority: Minor
>         Attachments: CASSANDRA-10140.txt
>
>
> Overhead for the gc logging is very small (with cycling logs in 7+) and it provides a ton of useful information. This will open up more for C* diagnostic tools to provide feedback as well without requiring restarts.



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