Re: Patch to implement pg_current_logfile() function

Re: Gilles Darold 2016-10-27 <ee7efb7d-fd41-4dfd-29ed-6d05044d1cbc(at)dalibo(dot)com>
> > I'm partial to "format <space> path" over just line number, because
> > it's more explicit. Either way works.
>
> This is the format used. Ex:
>
> ~$ cat /usr/local/postgresql/data/current_logfile
> stderr pg_log/postgresql-2016-10-27_185100.log
> csvlog pg_log/postgresql-2016-10-27_185100.csv

On a closer look, I like this better than my "always two lines"
suggestion. +1.

> -1, SHOW is used to display run-time parameters values in our case this
> is log_destination + log_directory + log_filename. current_logfile is a
> filename not a parameter name.

I'm not sure if it's even possible to put non-GUC information in
there. It might also be a performance problem, if pg_current_logfiles
had to read-in for every "select * from pg_settings".

Re: Karl O. Pinc 2016-10-27 <20161027121141(dot)6bd95efd(at)slate(dot)meme(dot)com>
> Another interface to consider might be a system catalog:
>
> SELECT * from postgres.pg_current_logfile;
>
> format | path
> -------+-------------------
> syslog | /some/where/log
> cvslog | /some/where/log.csv
>
> (2 rows)
>
> Maybe good if the goal is "interactive use". Seems like
> overkill to me, but thought I'd present the idea
> anyway.

We were discussing exactly that idea upthread before concluding that a
function with a single return value is much easier to use.

Christoph