Date: Tue, 10 Oct 2006 09:21:02 -0500
From: "Jim C. Nasby" <jim@nasby.net>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Tobias Brox <tobias@nordicbet.com>, Chris Browne <cbbrowne@acm.org>,
	pgsql-performance@postgresql.org
Subject: Re: Simple join optimized badly?
Message-ID: <20061010142101.GD72517@nasby.net>
References: <20061009213303.GA19144@oppetid.no>
	<20061009223030.GW72517@nasby.net> <9723.1160433916@sss.pgh.pa.us>
	<20061010140050.GZ72517@nasby.net> <17519.1160489688@sss.pgh.pa.us>
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On Tue, Oct 10, 2006 at 10:14:48AM -0400, Tom Lane wrote:
> "Jim C. Nasby" <jim@nasby.net> writes:
> > I'd rather have the ugly solution sooner rather than the elegant one
> > later (if ever).
> 
> The trouble with that is that we couldn't ever get rid of it, and we'd
> be stuck with backward-compatibility concerns with the first (over
> simplified) design.  It's important to get it right the first time,
> at least for stuff that you know perfectly well is going to end up
> embedded in application code.

We've depricated things before, I'm sure we'll do it again. Yes, it's a
pain, but it's better than not having anything release after release.
And having a formal hint language would at least allow us to eventually
clean up some of these oddball cases, like the OFFSET 0 hack.

I'm also not convinced that even supplimental statistics will be enough
to ensure the planner always does the right thing, so query-level hints
may have to stay (though it'd be great if that wasn't the case).
-- 
Jim Nasby                                            jim@nasby.net
EnterpriseDB      http://enterprisedb.com      512.569.9461 (cell)