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Posted to issues-all@impala.apache.org by "ASF subversion and git services (JIRA)" <ji...@apache.org> on 2019/03/25 22:30:01 UTC

[jira] [Commented] (IMPALA-7239) Mitigate ParseSmaps() overhead

    [ https://issues.apache.org/jira/browse/IMPALA-7239?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16801191#comment-16801191 ] 

ASF subversion and git services commented on IMPALA-7239:
---------------------------------------------------------

Commit 857515ca18f42add88aec634af042739730c88de in impala's branch refs/heads/2.x from Tim Armstrong
[ https://gitbox.apache.org/repos/asf?p=impala.git;h=857515c ]

IMPALA-7239: Disable smaps parsing by default

Accessing smaps has proven to be too expensive to enable on all
operating systems. Let's move the metrics behind a hidden flag
so that they can be enabled for development if needed but
won't affect production workloads.

Change-Id: I235eddde8fe925866e0581b235752354a3f36d5b
Reviewed-on: http://gerrit.cloudera.org:8080/10884
Reviewed-by: Impala Public Jenkins <im...@cloudera.com>
Tested-by: Impala Public Jenkins <im...@cloudera.com>


> Mitigate ParseSmaps() overhead
> ------------------------------
>
>                 Key: IMPALA-7239
>                 URL: https://issues.apache.org/jira/browse/IMPALA-7239
>             Project: IMPALA
>          Issue Type: Bug
>          Components: Backend
>    Affects Versions: Impala 2.10.0, Impala 2.11.0, Impala 3.0, Impala 2.12.0
>            Reporter: Tim Armstrong
>            Assignee: Tim Armstrong
>            Priority: Critical
>              Labels: perf, resource-management
>             Fix For: Impala 3.1.0
>
>         Attachments: mmap.c
>
>
> I've heard anecdotes of high system time spent in functions related this the smap parsing. It appears that this can be expensive on systems once the impalad virtual memory gets fragmented and there are 10s of thousands of maps.
> We can try to mitigate by reducing frequency of the parsing or disabling it entirely. I'm not sure if there are cheaper ways to get all of the same metrics.



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