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https://issues.apache.org/jira/browse/HIVE-22850?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17037495#comment-17037495
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Hive QA commented on HIVE-22850:
--------------------------------
Here are the results of testing the latest attachment:
https://issues.apache.org/jira/secure/attachment/12993445/HIVE-22850.6.patch
{color:red}ERROR:{color} -1 due to build exiting with an error
Test results:
https://builds.apache.org/job/PreCommit-HIVE-Build/20646/testReport
Console output: https://builds.apache.org/job/PreCommit-HIVE-Build/20646/console
Test logs: http://104.198.109.242/logs/PreCommit-HIVE-Build-20646/
Messages:
{noformat}
Executing org.apache.hive.ptest.execution.TestCheckPhase
Tests exited with: Exception: Patch URL
https://issues.apache.org/jira/secure/attachment/12993445/HIVE-22850.6.patch
was found in seen patch url's cache and a test was probably run already on it.
Aborting...
{noformat}
This message is automatically generated.
ATTACHMENT ID: 12993445 - PreCommit-HIVE-Build
> Optimise lock acquisition in TxnHandler
> ---------------------------------------
>
> Key: HIVE-22850
> URL: https://issues.apache.org/jira/browse/HIVE-22850
> Project: Hive
> Issue Type: Improvement
> Components: Hive
> Reporter: Rajesh Balamohan
> Priority: Major
> Attachments: HIVE-22850.1.patch, HIVE-22850.2.patch,
> HIVE-22850.3.patch, HIVE-22850.4.patch, HIVE-22850.6.patch, Screenshot
> 2020-02-07 at 4.14.51 AM.jpg, jumpTableInfo.png
>
>
> With concurrent queries, time taken for lock acquisition increases
> substantially. As part of lock acquisition in the query,
> {{TxnHandler::checkLock}} gets invoked. This involves getting a mutex and
> compare the locks being requested for, with that of existing locks in
> {{HIVE_LOCKS}} table.
> With concurrent queries, time taken to do this check increase and this
> significantly increases the time taken for getting mutex for other threads
> (due to select for update). In a synthetic workload, it was in the order of
> 10+ seconds. This codepath can be optimized when all lock requests are
> SHARED_READ.
>
>
> !Screenshot 2020-02-07 at 4.14.51 AM.jpg|width=743,height=348!
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