From: Richard Huxton <dev@archonet.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Brian Herlihy <btherl@yahoo.com.au>
Cc: pgsql-performance@postgresql.org
Subject: Spotting planner errors (was Re: Query planner is using wrong index.)
Date: Fri, 07 Apr 2006 16:08:10 +0100
Message-ID: <4436805A.1040507@archonet.com> (raw)
In-Reply-To: <11739.1144420493@sss.pgh.pa.us>
References: <20060407064108.49532.qmail@web52315.mail.yahoo.com>
<11739.1144420493@sss.pgh.pa.us>
Tom Lane wrote:
> Brian Herlihy <btherl@yahoo.com.au> writes:
>> Before I go, I have a question - From discussions on the Postgresql irc
>> channel, and from reading the TODO list on the website, I am under the
>> impression that there are no plans to allow optimizer hints, such as "use index
>> table_pkey". Is this really true?
>
> I personally don't think it's a good idea: the time spent in designing,
> implementing, and maintaining a usable hint system would be significant,
> and IMHO the effort is better spent on *fixing* the optimizer problems
> than working around them.
Tom - does the planner/executor know it's got row estimates wrong? That
is, if I'm not running an EXPLAIN ANALYSE is there a point at which we
could log "planner estimate for X out by factor of Y"?
--
Richard Huxton
Archonet Ltd
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To: pgsql-performance@postgresql.org
Cc: dev@archonet.com, tgl@sss.pgh.pa.us, btherl@yahoo.com.au
Subject: Re: Spotting planner errors (was Re: Query planner is using wrong index.)
In-Reply-To: <4436805A.1040507@archonet.com>
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