Re: Bad UI design: pg_ctl and data_directory

Alvaro Herrera <alvherre(at)commandprompt(dot)com> writes:
> Excerpts from Robert Haas's message of mi jun 01 18:22:56 -0400 2011:
>> ISTM that it would be useful to run postgres in a mode where it
>> doesn't actually try to start up the database, but parses
>> postgresql.conf and then exits, perhaps printing out the value of a
>> certain GUC as it does so. In this case, data_directory.

> I had the same thought, and wondered if we could use the feature
> elsewhere.

This was suggested quite some time ago, IIRC, but we never got round to it.

The main problem in the current context is that it only fixes the issue
so long as you ignore the possibility that relevant values were
specified on the command line or via environment variables, rather than
coming directly from the config file. PGDATA is thus a particular
hazard here: all you need is to be running with a different PGDATA
setting in your environment than was used when "pg_ctl start" was
issued, and you're hosed.

regards, tom lane