Re: Parallel worker hangs while handling errors.

From: vignesh C <vignesh21(at)gmail(dot)com>
To: Bharath Rupireddy <bharath(dot)rupireddyforpostgres(at)gmail(dot)com>
Cc: PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>, Robert Haas <robertmhaas(at)gmail(dot)com>
Subject: Re: Parallel worker hangs while handling errors.
Date: 2020-07-28 05:35:05
Message-ID: CALDaNm1O1mauSawnz-He3x6PPy91H_GMqWc9gsBezejm6QuZ+w@mail.gmail.com
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Thanks for your comments Bharath.

On Mon, Jul 27, 2020 at 10:13 AM Bharath Rupireddy
<bharath(dot)rupireddyforpostgres(at)gmail(dot)com> wrote:
> 1. Do we need "worker" as a function argument in
> update_parallel_worker_sigmask(BackgroundWorker *worker,.... ? Since
> MyBgworkerEntry is a global variable, can't we have a local variable
> instead?

Fixed, I have moved the worker check to the caller function.

> 2. Instead of update_parallel_worker_sigmask() serving only for
> parallel workers, can we make it generic, so that for any bgworker,
> given a signal it unblocks it, although there's no current use case
> for a bg worker unblocking a single signal other than a parallel
> worker doing it for SIGUSR1 for this hang issue. Please note that we
> have BackgroundWorkerBlockSignals() and
> BackgroundWorkerUnblockSignals().

Fixed. I have slightly modified the changes to break into
BackgroundWorkerRemoveBlockSignal & BackgroundWorkerAddBlockSignal.
This maintains the consistency similar to
BackgroundWorkerBlockSignals() and BackgroundWorkerUnblockSignals().

> If okay, with the BackgroundWorkerUpdateSignalMask() function, please
> note that we might have to add it in bgworker.sgml as well.

Included the documentation.

Attached the updated patch for the same.

Regards,
Vignesh
EnterpriseDB: http://www.enterprisedb.com

Attachment Content-Type Size
v4-0001-Fix-for-Parallel-worker-hangs-while-handling-erro.patch text/x-patch 4.6 KB

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