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Posted to issues-all@impala.apache.org by "ASF subversion and git services (Jira)" <ji...@apache.org> on 2023/06/02 22:39:00 UTC
[jira] [Commented] (IMPALA-10971) Data cache metrics count error when LIRS is enabled
[ https://issues.apache.org/jira/browse/IMPALA-10971?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17728884#comment-17728884 ]
ASF subversion and git services commented on IMPALA-10971:
----------------------------------------------------------
Commit 3c49ebad6b1c55305064ef905ef78b242b024c1f in impala's branch refs/heads/master from Joe McDonnell
[ https://gitbox.apache.org/repos/asf?p=impala.git;h=3c49ebad6 ]
IMPALA-10971: Fix data cache metrics for instant evictions
When inserting an entry into the data cache, the
Insert() can fail and instantly evict the new entry.
This is currently only true for the LIRS cache
eviction policy. When this happens, the cache metrics
are not maintained properly. The instant eviction
results in an unmatched decrement to the total bytes
and num entries counters.
This moves the increments to happen prior to the
Insert() call, which fixes the instant eviction
case. The behavior does not change noticeably for
the successful Insert() case.
Testing:
- Added custom cluster test to verify this case
Change-Id: I5db3eaca2f4459844e3270846d905f76265b6b3e
Reviewed-on: http://gerrit.cloudera.org:8080/19930
Reviewed-by: Joe McDonnell <jo...@cloudera.com>
Tested-by: Impala Public Jenkins <im...@cloudera.com>
> Data cache metrics count error when LIRS is enabled
> ---------------------------------------------------
>
> Key: IMPALA-10971
> URL: https://issues.apache.org/jira/browse/IMPALA-10971
> Project: IMPALA
> Issue Type: Bug
> Components: Backend
> Affects Versions: Impala 4.0.0
> Reporter: Ye Zihao
> Assignee: Joe McDonnell
> Priority: Minor
> Attachments: image-2021-10-18-14-15-52-422.png
>
>
> When LIRS is enabled, impala-server.io-mgr.remote-data-cache-total-bytes may give a wrong value because of INSTANT EVICTIONS. When INSTANT EVICTIONS occur, the total bytes decreases due to EvictedEntry, and no corresponding increase due to failure of insert, so the total bytes becomes smaller and smaller, or even negative.
> !image-2021-10-18-14-15-52-422.png!
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