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https://issues.apache.org/jira/browse/HIVE-20682?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16683274#comment-16683274
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Hive QA commented on HIVE-20682:
--------------------------------
Here are the results of testing the latest attachment:
https://issues.apache.org/jira/secure/attachment/12947774/HIVE-20682.06.patch
{color:green}SUCCESS:{color} +1 due to 2 test(s) being added or modified.
{color:green}SUCCESS:{color} +1 due to 15539 tests passed
Test results:
https://builds.apache.org/job/PreCommit-HIVE-Build/14880/testReport
Console output: https://builds.apache.org/job/PreCommit-HIVE-Build/14880/console
Test logs: http://104.198.109.242/logs/PreCommit-HIVE-Build-14880/
Messages:
{noformat}
Executing org.apache.hive.ptest.execution.TestCheckPhase
Executing org.apache.hive.ptest.execution.PrepPhase
Executing org.apache.hive.ptest.execution.YetusPhase
Executing org.apache.hive.ptest.execution.ExecutionPhase
Executing org.apache.hive.ptest.execution.ReportingPhase
{noformat}
This message is automatically generated.
ATTACHMENT ID: 12947774 - PreCommit-HIVE-Build
> Async query execution can potentially fail if shared sessionHive is closed by
> master thread.
> --------------------------------------------------------------------------------------------
>
> Key: HIVE-20682
> URL: https://issues.apache.org/jira/browse/HIVE-20682
> Project: Hive
> Issue Type: Bug
> Components: HiveServer2
> Affects Versions: 3.1.0, 4.0.0
> Reporter: Sankar Hariappan
> Assignee: Sankar Hariappan
> Priority: Major
> Labels: pull-request-available
> Attachments: HIVE-20682.01.patch, HIVE-20682.02.patch,
> HIVE-20682.03.patch, HIVE-20682.04.patch, HIVE-20682.05.patch,
> HIVE-20682.06.patch
>
>
> *Problem description:*
> The master thread initializes the *sessionHive* object in *HiveSessionImpl*
> class when we open a new session for a client connection and by default all
> queries from this connection shares the same sessionHive object.
> If the master thread executes a *synchronous* query, it closes the
> sessionHive object (referred via thread local hiveDb) if
> {{Hive.isCompatible}} returns false and sets new Hive object in thread local
> HiveDb but doesn't change the sessionHive object in the session. Whereas,
> *asynchronous* query execution via async threads never closes the sessionHive
> object and it just creates a new one if needed and sets it as their thread
> local hiveDb.
> So, the problem can happen in the case where an *asynchronous* query is being
> executed by async threads refers to sessionHive object and the master thread
> receives a *synchronous* query that closes the same sessionHive object.
> Also, each query execution overwrites the thread local hiveDb object to
> sessionHive object which potentially leaks a metastore connection if the
> previous synchronous query execution re-created the Hive object.
> *Possible Fix:*
> The *sessionHive* object could be shared my multiple threads and so it
> shouldn't be allowed to be closed by any query execution threads when they
> re-create the Hive object due to changes in Hive configurations. But the Hive
> objects created by query execution threads should be closed when the thread
> exits.
> So, it is proposed to have an *isAllowClose* flag (default: *true*) in Hive
> object which should be set to *false* for *sessionHive* and would be
> forcefully closed when the session is closed or released.
> Also, when we reset *sessionHive* object with new one due to changes in
> *sessionConf*, the old one should be closed when no async thread is referring
> to it. This can be done using "*finalize*" method of Hive object where we can
> close HMS connection when Hive object is garbage collected.
> cc [~pvary]
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