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https://issues.apache.org/jira/browse/HAWQ-1334?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Paul Guo reassigned HAWQ-1334:
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Assignee: Paul Guo (was: Ed Espino)
> QD thread should set error code if failing so that the main process for the
> query could exit soon
> -------------------------------------------------------------------------------------------------
>
> Key: HAWQ-1334
> URL: https://issues.apache.org/jira/browse/HAWQ-1334
> Project: Apache HAWQ
> Issue Type: Bug
> Components: Dispatcher
> Reporter: Paul Guo
> Assignee: Paul Guo
>
> In QD thread function dispmgt_thread_func_run(), if there are failures either
> due to QE or QD itself, it will cancel the query and then clean up. The main
> process for the query needs the error code of meleeResults be set so that it
> soon proceeds to cancel the query, else we have to wait for timeout.
> Typically dispmgt_thread_func_run() should set the error code, however I
> found there are some cases who do not handle this, e.g. if poll() fails with
> ENOMEM. One symptom of this issue is that we could sometimes see hang if a
> query is canceled for some reasons.
> The potential solution is that:
> 1) We expect each branch jump ("goto error_cleanup") set proper error code
> itself. It is not an easy job.
> 2) We add a "guard" function in the error_cleanup code to set an error code
> if it is not set, i.e. 1) is not well done.
> I'd this JIRA cares about 2).
> In general, the cleanup code in QD seems to be really obscure and not
> elegant. Maybe we should file another JIRA to refactor the error handling
> logic in it.
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