Horton

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

Bruce Momjian <bruce@momjian.us>

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From: Bruce Momjian <bruce@momjian.us>
To: Alvaro Herrera <alvherre@commandprompt.com>
Cc: Peter Eisentraut <peter_e@gmx.net>, Fujii Masao <masao.fujii@gmail.com>, "Mr. Aaron W. Swenson" <titanofold@gentoo.org>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2011-10-03T19:09:08Z
Lists: pgsql-hackers

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  1. Fix nested PlaceHolderVar expressions that appear only in targetlists.

Alvaro Herrera wrote:
> 
> Excerpts from Bruce Momjian's message of lun oct 03 15:23:47 -0300 2011:
> > Peter Eisentraut wrote:
> > > On m?n, 2011-10-03 at 11:27 -0400, Bruce Momjian wrote:
> > > > Frankly, I am confused how this breakage has gone unreported for so
> > > > long.
> > > 
> > > Well, nobody is required to use pg_ctl, and for the longest time, it was
> > > pg_ctl that was considered to be broken (for various other reasons) and
> > > avoided in packaged init scripts.
> > 
> > Yes, but I am now seeing that pg_ctl is really unfixable.  Is the
> > config-only directory really a valuable feature if pg_ctl does not work?
> > 
> > If we could document that pg_ctl (and pg_upgrade) doesn't work with
> > config-only directories, at least we would have a consistent API.  The
> > question is whether the config-only directory is useful with this
> > restriction.
> 
> Evidently people that use config-only dirs don't care all that much
> about pg_ctl; we'd have a lot of bugs about it otherwise.  But I don't
> think that's the case for pg_upgrade.  I think that simply dictating the
> combination of conf-only dirs and pg_upgrade doesn't work is not going
> to be a very popular choice, particularly if there's a simple workaround
> such as adding a symlink.  (This makes me wonder, though, we don't we
> require that said symlink is always in place; maybe have postmaster
> create it automatically if it's not present?)
> 
> 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. :-(

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.

Why were people not using pg_ctl?  Because of the limitations which were
fixed in PG 9.1?  As Dave already said, windows already has to use pg_ctl.

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + It's impossible for everything to be true. +