Date: Mon, 9 Oct 2006 23:33:03 +0200
From: Tobias Brox <tobias@nordicbet.com>
To: "Jim C. Nasby" <jim@nasby.net>
Cc: Chris Browne <cbbrowne@acm.org>, pgsql-performance@postgresql.org
Subject: Re: Simple join optimized badly?
Message-ID: <20061009213303.GA19144@oppetid.no>
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[Jim C. Nasby - Mon at 04:18:27PM -0500]
> I can agree to that, but we'll never get any progress so long as every
> time hints are brought up the response is that they're evil and should
> never be in the database. I'll also say that a very simple hinting
> language (ie: allowing you to specify access method for a table, and
> join methods) would go a huge way towards enabling app developers to get
> stuff done now while waiting for all these magical optimizer
> improvements that have been talked about for years.

Just a comment from the side line; can't the rough "set
enable_seqscan=off" be considered as sort of a hint anyway?  There have
been situations where we've actually had to resort to such crud.

Beeing able to i.e. force a particular index is something I really
wouldn't put into the application except for as a very last resort,
_but_ beeing able to force i.e. the use of a particular index in an
interactive 'explain analyze'-query would often be ... if not outright
useful, then at least very interessting.