Horton

Printing backtrace of postgres processes

vignesh C <vignesh21@gmail.com>

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From: vignesh C <vignesh21@gmail.com>
To: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2020-11-22T03:06:25Z
Lists: pgsql-hackers

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Hi,

I would like to propose getting the callstack of the postgres process
by connecting to the server. This helps us in diagnosing the problems
from a customer environment in case of hung process or in case of long
running process.
The idea here is to implement & expose pg_print_callstack function,
internally what this function does is, the connected backend will send
SIGUSR1 signal by setting PMSIGNAL_BACKTRACE_EMIT to the postmaster
process. Postmaster process will send a SIGUSR1 signal to the process
by setting PROCSIG_BACKTRACE_PRINT if the process has access to
ProcSignal. As syslogger process & Stats process don't have access to
ProcSignal, multiplexing with SIGUSR1 is not possible for these
processes, hence SIGUSR2 signal will be sent for these processes. Once
the process receives this signal it will log the backtrace of the
process.
Attached is a WIP patch for the same.
Thoughts?

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

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