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https://issues.apache.org/jira/browse/IMPALA-8316?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16801193#comment-16801193
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ASF subversion and git services commented on IMPALA-8316:
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Commit 25559dd43cf25cd010b902f314b5a50c88c35228 in impala's branch
refs/heads/master from Thomas Tauber-Marshall
[ https://gitbox.apache.org/repos/asf?p=impala.git;h=25559dd ]
Bump toolchain version to 8430101a-b65f-4e4d-921e-767771649ae4-713afc77a8
This bumps the version of two toolchain components:
- IMPALA-8316: Update re2 to the latest version
This updates re2 to the latest tagged release from github.
Todd Lipcon benchmarked this with a simple query:
select sum(l_linenumber) from item_20x where
length(regexp_extract(l_shipinstruct, '.*', 0)) > 0
Prior to the change:
- TotalCpuTime: 42s848ms
- wall time: ~19sec
With the change:
- TotalCpuTime: 33s634ms
- wall time: 14-15sec
- This patch also bumps the toolchain Kudu version to 1.9.0
Change-Id: Ie9298709c534beeccfe36e212e0064d575cec9ac
Reviewed-on: http://gerrit.cloudera.org:8080/12824
Reviewed-by: Impala Public Jenkins <[email protected]>
Tested-by: Impala Public Jenkins <[email protected]>
> Update re2 to avoid lock contention
> -----------------------------------
>
> Key: IMPALA-8316
> URL: https://issues.apache.org/jira/browse/IMPALA-8316
> Project: IMPALA
> Issue Type: Improvement
> Components: Backend
> Reporter: Todd Lipcon
> Assignee: Todd Lipcon
> Priority: Major
> Labels: perf
> Fix For: Impala 3.3.0
>
>
> I ran the following test query and found that it spent a lot of time in lock
> contention within the re2 library:
> ```select sum(l_linenumber) from item_20x where
> regexp_extract(l_shipinstruct, '.*E', 0) like '%E' ;```
> I think this lock contention would happen on any regex that involves
> backtracking. This was fixed in the re2 library upstream in
> https://github.com/google/re2/commit/eb00dfdd82015be22086cacc6bf830f72a10e2bc#diff-a60a8d25ed15adf68b94c85775fd3cf7
> We should consider upgrading re2 to the latest release, or if not that, at
> least cherry-picking this perf fix.
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