Re: PostgreSQL configuration

pgsql(at)mohawksoft(dot)com writes:
> I am neither suggesting nor implementing any change in the current default
> behavior of PostgreSQL. I am merely adding features that would make it
> easier to do things like configure from a centralized directory which is
> different than the data directory, the ability to included
> "sub-configuration" like specific tuning or debug info, and to write a
> usable PID file for standard UNIX admin scripts.

Well, let's take it one piece at a time here.

I can see some value in providing "#include" functionality in
postgresql.conf (and the other config files too). I'm not convinced
that it's a must-have, because the desired contents of the config files
tend to change with each new PG version. But to the extent that you're
admining multiple clusters of the same version, it would have some use.

Moving the PID file out of the data directory is actively dangerous,
because we use that file as part of the safety interlock against
starting multiple postmasters in the same data directory. I suppose
we could offer an option to write a second copy of the PID file at
a different place, but I'm not seeing what that buys except confusion
(especially if two postmasters are mistakenly instructed to put their
copied PID files at the same place).

The whole idea of having multiple command-line switches to pick config
and data separately bothers me. ISTM this would mostly create great new
opportunities to shoot yourself in the foot (by accidentally picking the
wrong combination), without nearly enough benefit to outweigh the risk.
Possibly this perspective is somewhat developer-centric --- I'm sure
I manually start postmasters far more often than the average person.
But then this whole discussion seems of interest only to people with
outlier requirements; the existing setup works fine for the average user
with only one Postgres installation.

Could we compromise on just adding #include functionality? ISTM that
would cover the desire for separate config and data directories. You
could keep a postgresql.conf file in each data directory that simply
says
#include /etc/postgres/debug.conf
and likewise for other config files. Doesn't that accomplish what you
want?

regards, tom lane