Re: Bug with pg_ctl -w/wait and config-only directories

Excerpts from Bruce Momjian's message of lun oct 03 16:55:54 -0300 2011:
> 
> Alvaro Herrera wrote:
> > 
> > Excerpts from Bruce Momjian's message of lun oct 03 16:09:08 -0300 2011:
> > 
> > > Alvaro Herrera wrote:
> > 
> > > > My guess is that we could fix the simple case (the one that doesn't
> > > > involve a "-o datadir" option) with the parse-and-report option that has
> > > > been mentioned, and dictate that the other one doesn't work.  That's
> > > > much less likely to cause a problem in practice.
> > > 
> > > Well, we are unlikely to backpatch that parse-and-report option so it
> > > would be +2 years before it could be expected to work for even
> > > single-major-version upgrades.  That just seems unworkable.  Yeah. :-(
> > 
> > If we don't do anything, then it's never going to work.  If we do it
> > today, we can have it working in the next release (9.2, right?).
> 
> No, old and new have to support this in both the postgres and pg_ctl
> binaries, which is why I said 2+ years, e.g. going from 9.1 to 9.3 is
> not going to work, unless we backpatch, and then we have to make sure
> users are on later minor versions.

Well, so 2 releases.  Same argument.  I hope you're not trying to imply
that the world will end in 2013.  (Note that I don't necessarily
disagree with Robert Haas' opinion that we might be able to backpatch
the postmaster option).


> > > Yes, auto-creation of symlinks would be useful, but at that point pg_ctl
> > > and pg_upgrade would have to use the real data directory, so I again
> > > wonder what the config-only directory is getting us.
> > 
> > Not mixing config stuff (in /etc per FHS) with server data (/var/lib,
> > again per FHS).  It's Debian policy anyway.  I don't judge whether this
> > is sane or not.  See
> > http://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard
> 
> Yes, but why not do this via symlinks?

It doesn't matter now, because we have the functionality already.

> The problem is pg_ctl has to read server _state_ which cannot be put
> in a configuration directory, and we don't even require the real data
> directory to be recorded in the config file.

How so?  It certainly is in postgresql.conf.

-- 
Álvaro Herrera <alvherre@commandprompt.com>
The PostgreSQL Company - Command Prompt, Inc.
PostgreSQL Replication, Consulting, Custom Development, 24x7 support