Re: Patch to implement pg_current_logfile() function

Gilles Darold <gilles(dot)darold(at)dalibo(dot)com> writes:
> Le 11/03/2016 10:49, Shulgin, Oleksandr a crit :
>> Would it make sense to have it as a symlink instead?

> The only cons I see is that it can be more "difficult" with some
> language to gather the real path, but do we really need it? There is
> also little time where the symlink doesn't exist, this is when it needs
> to be removed before being recreated to point to the new log file.

Yeah, a symlink is impossible to update atomically (on most platforms
anyway). Plain file containing the pathname seems better.

Another point is that we might not necessarily want *only* the pathname in
there. postmaster.pid has accreted more stuff over time, and this file
might too. I can see wanting the syslogger PID in there, for example,
so that onlookers can detect a totally stale file. (Not proposing this
right now, just pointing out that it's a conceivable future feature.)

regards, tom lane