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https://issues.apache.org/jira/browse/DRILL-6325?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16434693#comment-16434693
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Timothy Farkas commented on DRILL-6325:
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There are also data structures accessed by multiple threads that are not
synchronized in QueryManager
> Memory usage stats may not be updated correctly for an operator.
> ----------------------------------------------------------------
>
> Key: DRILL-6325
> URL: https://issues.apache.org/jira/browse/DRILL-6325
> Project: Apache Drill
> Issue Type: Bug
> Reporter: Timothy Farkas
> Assignee: Timothy Farkas
> Priority: Major
>
> The memory usage stats for an operator in a query profile may not be up to
> date, even after the query is completed. This is caused by two possible
> issues:
> 1 Memory usage is polled by a thread once every 5 seconds. However the final
> memory usage of the operator may not be reported if the operator completes
> before the next polling cycle.
> 2 There is a race condition in the Foreman where one thread sets the metrics
> on an object and another thread reads the metrics object to include in a
> query profile. The thread that reads the metrics object may read old metrics
> since access to the variable is not synchronized.
> There are two fixes for this
> 1 Poll the stats one more time after the fragment root completes but before
> the operator is closed.
> 2 Synchronize the methods on the FragmentData class.
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