Re: Printing backtrace of postgres processes

On Mon, Nov 15, 2021 at 11:37 AM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
>
> On Mon, Nov 15, 2021 at 10:34 AM vignesh C <vignesh21(at)gmail(dot)com> wrote:
>
> >
> > Thanks for the comments, the attached v12 patch has the changes for the same.
>
> I have reviewed this patch and have some comments on v12-0001,
>
> 1.
> + This feature is not supported for the postmaster, logger, checkpointer,
> + walwriter, background writer or statistics collector process. This
>
>
> Comment says it is not supported for postmaster, logger, checkpointer
> etc, but I just tried and it is working for checkpointer and walwriter
> processes, can you explain in comments why do we not want to support
> for these processes? or the comment is old and now we are supporting
> for some of these processes.

Please see the v12-0002 which will have the description modified.

> 2.
> postgres[64154]=# select pg_print_backtrace(64136);
> WARNING: 01000: PID 64136 is not a PostgreSQL server process
> LOCATION: pg_print_backtrace, signalfuncs.c:335
> pg_print_backtrace
> --------------------
> f
>
>
> For postmaster I am getting this WARNING "PID 64136 is not a
> PostgreSQL server process", even if we don't want to support this
> process I don't think this message is good.

This is a generic message that is coming from pg_signal_backend, not
related to Vignesh's patch. I agree with you that emitting a "not
postgres server process" for the postmaster process which is the main
"postgres process" doesn't sound sensible. Please see there's already
a thread [1] and see the v1 patch [2] for changing this message.
Please let me know if you want me to revive that stalled thread?

[1] https://www.postgresql.org/message-id/CALj2ACW7Rr-R7mBcBQiXWPp%3DJV5chajjTdudLiF5YcpW-BmHhg%40mail.gmail.com
[2] https://www.postgresql.org/message-id/CALj2ACUGxedgYk-5nO8D2EJV2YHXnoycp_oqYAxDXTODhWkmkg%40mail.gmail.com

Regards,
Bharath Rupireddy.