Re: strange parallel query behavior after OOM crashes - Mailing list pgsql-hackers

From Kuntal Ghosh
Subject Re: strange parallel query behavior after OOM crashes
Date
Msg-id CAGz5QCJ1MEKYzGnOJxWHK039ToKQVnj=BrT7BiQiAzH-jTgZrA@mail.gmail.com
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Responses Re: strange parallel query behavior after OOM crashes  (Neha Khatri <nehakhatri5@gmail.com>)
Re: strange parallel query behavior after OOM crashes  (Robert Haas <robertmhaas@gmail.com>)
List pgsql-hackers
On Fri, Mar 31, 2017 at 6:50 PM, Robert Haas <robertmhaas@gmail.com> wrote:
> On Thu, Mar 30, 2017 at 4:35 PM, Kuntal Ghosh
> <kuntalghosh.2007@gmail.com> wrote:
>> 2. the server restarts automatically, initialize
>> BackgroundWorkerData->parallel_register_count and
>> BackgroundWorkerData->parallel_terminate_count in the shared memory.
>> After that, it calls ForgetBackgroundWorker and it increments
>> parallel_terminate_count.
>
> Hmm.  So this seems like the root of the problem.  Presumably those
> things need to be reset AFTER forgetting any background workers from
> before the crash.
>
IMHO, the fix would be not to increase the terminated parallel worker
count whenever ForgetBackgroundWorker is called due to a bgworker
crash. I've attached a patch for the same. PFA.



-- 
Thanks & Regards,
Kuntal Ghosh
EnterpriseDB: http://www.enterprisedb.com

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