Re: Printing backtrace of postgres processes

On Tue, Dec 1, 2020 at 9:31 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
> Andres Freund <andres(at)anarazel(dot)de> writes:
> > It should be quite doable to emit such backtraces directly to stderr,
> > instead of using appendStringInfoString()/elog().
>
> No, please no.
>
> (1) On lots of logging setups (think syslog), anything that goes to
> stderr is just going to wind up in the bit bucket. I realize that
> we have that issue already for memory context dumps on OOM errors,
> but that doesn't make it a good thing.
>
> (2) You couldn't really write "to stderr", only to fileno(stderr),
> creating issues about interleaving of the output with regular stderr
> output. For instance it's quite likely that the backtrace would
> appear before stderr output that had actually been emitted earlier,
> which'd be tremendously confusing.
>
> (3) This isn't going to do anything good for my concerns about interleaved
> output from different processes, either.
>

I felt if we are not agreeing on logging on the stderr, even using
static buffer we might not be able to log as
send_message_to_server_log calls appendStringInfo. I felt that doing
it from CHECK_FOR_INTERRUPTS may be better.

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