[jira] [Commented] (KAFKA-2992) Trace log statements in the replica fetcher inner loop create large amounts of garbage

["Ismael Juma (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/KAFKA-2992?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15059219#comment-15059219 ] 

Ismael Juma commented on KAFKA-2992:
------------------------------------

Thanks for reporting. I think it would be interesting to fix the issue generally. A combination of inline annotations and making the logger a class could do it, but needs testing.

> Trace log statements in the replica fetcher inner loop create large amounts of garbage
> --------------------------------------------------------------------------------------
>
>                 Key: KAFKA-2992
>                 URL: https://issues.apache.org/jira/browse/KAFKA-2992
>             Project: Kafka
>          Issue Type: Improvement
>          Components: core
>    Affects Versions: 0.8.2.1, 0.9.0.0
>         Environment: Centos 6, Java 1.8.0_20
>            Reporter: Cory Kolbeck
>            Priority: Minor
>              Labels: garbage, logging, trace
>             Fix For: 0.8.1.2, 0.10.0.0
>
>
> We're seeing some GC pause issues in production, and during our investigation found that the thunks created during invocation of three trace statements guarded in the attached PR were responsible for ~98% of all allocations by object count and ~90% by size. While I'm not sure that this was actually the cause of our issue, it seems prudent to avoid useless allocations in a tight loop.
> I realize that the trace() call does its own guarding internally, however it's insufficient to prevent allocation of the thunk. I can work on getting profiling results to attach here, but I used YourKit and the license has since expired.



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