[jira] [Commented] (HIVE-18837) add a flag and disable some object pools in LLAP until further testing

["Prasanth Jayachandran (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HIVE-18837?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16382895#comment-16382895 ] 

Prasanth Jayachandran commented on HIVE-18837:
----------------------------------------------

lgtm, +1. Pending tests

> add a flag and disable some object pools in LLAP until further testing
> ----------------------------------------------------------------------
>
>                 Key: HIVE-18837
>                 URL: https://issues.apache.org/jira/browse/HIVE-18837
>             Project: Hive
>          Issue Type: Bug
>            Reporter: Sergey Shelukhin
>            Assignee: Sergey Shelukhin
>            Priority: Major
>         Attachments: HIVE-18837.patch
>
>
> There appears to be some subtle concurrency issue in FixedSizedObjectPool that happens with multiple consumers where some object may be retrieved twice. 
> Unfortunately running a load test for hour(s) does not trigger it for me and overall it happens extremely rarely on non-specific tests; adding debug info at this level is a little bit difficult to determine how it could have happened and interlocked operations in the trace may actually eliminate the issue. I suspect it has something to do with aggressive assumptions made for locking and array elements and the memory model. Maybe that can be simplified without much perf loss.
> Anyway, for now we will disable the pools where multiple consumers use them.
> Need to test perf to see if these two pools even matter; if so, we can simplify the model as per above or debug the issue in some way.



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