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Posted to issues@impala.apache.org by "Doug Cameron (JIRA)" <ji...@apache.org> on 2017/05/31 02:34:04 UTC

[jira] [Created] (IMPALA-5393) Regexp should use THREAD_LOCAL context rather than FRAGMENT_LOCAL

Doug Cameron created IMPALA-5393:
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             Summary: Regexp should use THREAD_LOCAL context rather than FRAGMENT_LOCAL
                 Key: IMPALA-5393
                 URL: https://issues.apache.org/jira/browse/IMPALA-5393
             Project: IMPALA
          Issue Type: Improvement
          Components: Backend
    Affects Versions: Impala 2.8.0
            Reporter: Doug Cameron
            Assignee: John Sherman
            Priority: Minor


The RE2 library uses mutex locking around some internal state structures.  This causes severe lock contention and lack of CPU scaling on the regexp string function.

Switching to THREAD_LOCAL context will remove the contention.

We could add a query option to select between FRAGMENT_LOCAL vs THREAD_LOCAL but that seems overkill as the context is not huge.
 



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