Andrew Sullivan <andrew@libertyrms.info> writes:
> a. The system uses no environment variables at all; some other
> method is used to determine where the config file is (maybe compiled
> into the code);
> If I understand it, nobody is really arguing for (a).
I am. I see absolutely no advantage in depending on environment
variables rather than a config file. Here's another point beyond the
ones I've made already: config files are self-documenting if we set them
up in the style used by postgresql.conf (ie, comments showing all the
allowed settings) --- self-documenting with respect to both what you
might do, and what you actually have done in the running system.
Environment variables are not; do you know exactly which strings in your
environment affect Postgres, or what other settings you might have made
but didn't? Where would you go to find out? (This is partly a failure
of documentation, no doubt, but the point about a config file is that it
offers an extremely obvious place to find out.) Also, how could you
find out the actual configuration of a running server ... especially
if you are admining it remotely? We have SHOW for GUC variables, and
nothing at all for environment variables.
Bottom line: we have an extremely nice configuration engine in place
already. I really fail to understand why we want to ignore it and
emulate inferior pre-GUC approaches.
regards, tom lane