Horton

Re: Printing backtrace of postgres processes

Tom Lane <tgl@sss.pgh.pa.us>

View thread View on postgr.es
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
Cc: vignesh C <vignesh21@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2020-12-01T04:01:25Z
Lists: pgsql-hackers 
Andres Freund <andres@anarazel.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.

			regards, tom lane

Commits

  1. Perform apply of large transactions by parallel workers.

  2. Enhance pg_log_backend_memory_contexts() for auxiliary processes.

  3. Allow GRANT on pg_log_backend_memory_contexts().

  4. Move Perl test modules to a better namespace

  5. Unify PostgresNode's new() and get_new_node() methods

  6. Add backtrace support for error reporting