Re: Reopen logfile on SIGHUP

Anastasia Lubennikova <a(dot)lubennikova(at)postgrespro(dot)ru> writes:

> Large percentage of postgres installations, for example PGDG packages
> for Debian/Ubuntu, assume by default that log management will be
> handled by extrernals tools such as logrotate.
>
> Unfortunately such tools have no way to tell postgres to reopen log
> file after rotation and forced to use copy-truncate strategy that
> leads to a loss of log messages which is unacceptable.
>
> Small patch in the attachment implements logfile reopeninig on SIGHUP.
> It only affects the file accessed by logging collector, which name you
> can check with pg_current_logfile().
>
> I hope you will find this feature useful.

+1 for the feature, but:

> syslogFile = logfile_open(last_file_name, "a", false);

This will cause a fatal error if opening the logfile fails for any
reason (even transient errors like ENFILE/EMFILE). There is already the
logfile_rotate() function that can reopen log files safely based on time
and date limits. I'd suggest extending that by adding a config option
that controls whether to always reopen the log file on SIGHUP.

- ilmari
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