Re: [HACKERS] PGXLOG variable worthwhile?

On Wed, 18 Sep 2002, Bruce Momjian wrote:

> Sorry, I don't see the logic here. Using postgresql.conf, you set it
> once and it remains set until you change it again. With -X, you have to
> use it every time. I think that's where the votes came from.

Ah, so you are saying that you type out your full command line each and
every time you start up the server? I know, in my case, I have a shell
script setup that I edit my changes in so that I don't have to remember
...

> You argued that -X and GUC make sense, but why add -X when can get it
> done at once in postgresql.conf. Also, consider changing the location
> does require moving the WAL files, so you already have this extra step.
> Adding to postgresql.conf is easy. I don't think you can just point it
> at a random empty directory on startup. Our goal was to reduce params
> to postmaster/postgres in favor of GUC, not add to them.

I don't disagree that editing postgresql.conf is easy, but its not
something that ppl would naturally thing of ... if I want to move a
directory with most servers I run, I will generally do a man to find out
what command options are required to do this change, and, if none are
provided, just create a god-forsaken symlink ...

The man page for postmaster should have something in it like:

-X <directory> Specifies an alternate location for WAL files. Superseded
by setting xlog_path in postmaster.conf

Hell, if you are going to remove -X because its 'easier to do it in
postmaster.conf', you should be looking at removing *all* command line
args that are better represented in the postmaster.conf file ...

The only time that *I* use the postmaster.conf file is when I'm playing
with the various scan'ng options ... why?

mars# ps aux | grep -- B
pgsql 133 0.0 0.0 77064 1512 con- S Mon10PM 3:21.15 /usr/local/bin/postmaster -B 8192 -N 512 -o -S 4096 -i -p 5432 -D/v1/pgsql (postgres)
pgsql 144 0.0 0.0 1097300 1372 ?? Is Mon10PM 0:06.04 /usr/local/pgsql/bin/postmaster -B 131072 -N 2048 -i -p 5433 -D/usr/local/pgsql/5433 -S (postgres)

its nice to be able to do a simple ps to find out which process is which,
and pointing where ... other then -D, I don't believe there is one option
in there that I couldn't have set in the postmaster.conf file, but, then,
to find out the various settings, I'd have to do ps to figure out where
the database files are stored, and then go look at the postmaster.conf
file to figure out what each are set to ...

I have one server that has 10 instances running right now:

jupiter# ps ax | grep -- -B
373 ?? Ss 0:55.31 /usr/local/pgsql721/bin/postmaster -B 10240 -N 512 -i -p 5432 -D/v1/pgsql/5432 -S (postgres)
383 ?? Ss 0:11.78 /usr/local/pgsql/bin/postmaster -B 64 -N 16 -i -p 5434 -D/v1/pgsql/5434 -S (postgres)
394 ?? Ss 0:17.82 /usr/local/pgsql/bin/postmaster -B 1024 -N 256 -i -p 5437 -D/v1/pgsql/5437 -S (postgres)
405 ?? Ss 0:16.46 /usr/local/pgsql/bin/postmaster -B 256 -N 128 -i -p 5440 -D/v1/pgsql/5440 -S (postgres)
416 ?? Ss 0:10.93 /usr/local/pgsql/bin/postmaster -B 256 -N 128 -i -p 5449 -D/v1/pgsql/5449 -S (postgres)
427 ?? Ss 0:16.30 /usr/local/pgsql/bin/postmaster -B 2048 -N 256 -i -p 5443 -D/v1/pgsql/5443 -S (postgres)
438 ?? Ss 0:10.60 /usr/local/pgsql721/bin/postmaster -B 1024 -N 512 -i -p 5446 -D/v1/pgsql/5446 -S (postgres)
88515 ?? Ss 0:10.05 /usr/local/pgsql/bin/postmaster -B 64 -N 16 -i -p 5433 -D/v1/pgsql/5433 -S (postgres)
13029 pi S+ 0:00.00 grep -- -B
445 con- S 0:10.59 /usr/local/pgsql/mb/bin/postmaster -B 256 -N 128 -i -p 5448 -D/v1/pgsql/openacs4 (postgres)
460 con- S 0:10.40 /usr/local/pgsql/bin/postmaster -B 64 -N 16 -i -p 5436 -D/v1/pgsql/electrichands (postgres)

All the information for each are right there in front of me ... I don't
have to go through 10 postmaster.conf files to figure out anything ...

the GUC value should override the command line option, agreed ... but the
ability to use the command line should not be removed just because some
ppl aren't competent enough to adjust their startup scripts if they change
their system ...