Received: from localhost (unknown [200.46.204.183]) by mail.postgresql.org (Postfix) with ESMTP id 02097650408 for ; Fri, 12 Dec 2008 14:23:31 -0400 (AST) Received: from mail.postgresql.org ([200.46.204.86]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 25720-04 for ; Fri, 12 Dec 2008 14:23:23 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from outmail136084.authsmtp.net (outmail136084.authsmtp.net [62.13.136.84]) by mail.postgresql.org (Postfix) with ESMTP id 8FDB265042C for ; Fri, 12 Dec 2008 14:23:22 -0400 (AST) Received: from mail-c188.authsmtp.com (mail-c188.authsmtp.com [62.13.128.25]) by punt5.authsmtp.com (8.14.2/8.14.2/Kp) with ESMTP id mBCIMcwX066167; Fri, 12 Dec 2008 18:22:38 GMT Received: from [192.168.0.3] (85-211-226-82.dyn.gotadsl.co.uk [85.211.226.82]) (authenticated bits=0) by mail.authsmtp.com (8.14.2/8.14.2/Kp) with ESMTP id mBCIMaa1088711; Fri, 12 Dec 2008 18:22:36 GMT Subject: Re: benchmarking the query planner From: Simon Riggs To: Tom Lane Cc: Gregory Stark , Robert Haas , Kevin Grittner , "jd@commandprompt.com" , Josh Berkus , Greg Smith , pgsql-hackers@postgresql.org In-Reply-To: <7928.1229105400@sss.pgh.pa.us> References: <603c8f070812061019r5aca3aajeaa5493b11c5feff@mail.gmail.com> <603c8f070812092025k6325e0fcud001b205a507a634@mail.gmail.com> <4313.1228931932@sss.pgh.pa.us> <603c8f070812101828p1bd7df49yb8c916adedb49fe1@mail.gmail.com> <9565.1229018968@sss.pgh.pa.us> <1229033073.13078.179.camel@hp_dx2400_1> <87ej0etkfh.fsf@oxford.xeocode.com> <1229039044.13078.193.camel@hp_dx2400_1> <4136ffa0812111823u645b6ec9wdca60b3da4b00499@mail.gmail.com> <1229072675.13078.196.camel@hp_dx2400_1> <603c8f070812120344m67ef2c1fs41806cfb4ff9e396@mail.gmail.com> <1229093975.13078.275.camel@ebony.2ndQuadrant> <87tz99s7bu.fsf@oxford.xeocode.com> <6558.1229098576@sss.pgh.pa.us> <1229101094.8673.44.camel@ebony.2ndQuadrant> <7928.1229105400@sss.pgh.pa.us> Content-Type: text/plain Date: Fri, 12 Dec 2008 18:22:20 +0000 Message-Id: <1229106140.8673.80.camel@ebony.2ndQuadrant> Mime-Version: 1.0 X-Mailer: Evolution 2.12.0 Content-Transfer-Encoding: 7bit X-Server-Quench: da86887b-c879-11dd-aecc-001871e930f4 X-AuthRoute: OCdxZQATClZOTQEd DAteCiNZVAwpPBRK HVkIKg5MJUcNSQVJ NksafhtFaQdbaVxS HGQLW1xEUVV7W2F/ aA0fZQBDYEtPQQdo VlZBQE1QEQdtHhxP W2xtK2QjJgRGcHZ3 ZEcsX3lSVQouJE57 SkZTR3BVbWBpdWEe BBRFJlYHIx5Kfh5N bVEqXXANN2FJBC9q VzwTFhsSEA9kHWxf TwcGLVcbW0UKGDF0 WxAPVSwyEFcUDz03 JhogJ0R0 X-Authentic-SMTP: 61633235383639.cat.dmpriest.net.uk:1378/Kp X-Report-SPAM: If SPAM / abuse - report it at: http://www.authsmtp.com/abuse X-Virus-Status: No virus detected - but ensure you scan with your own anti-virus system! X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=0 tagged_above=0 required=5 tests=none X-Spam-Level: X-Archive-Number: 200812/981 X-Sequence-Number: 129610 On Fri, 2008-12-12 at 13:10 -0500, Tom Lane wrote: > If we don't > have at least ballpark-correct figures for cost and number of output > rows, we'll start making mistakes at higher plan levels. That's definitely where we are now. Had a call with a customer today where I said "it's OK, its only out by 3 orders of magnitude, it gets worse than that". 9 hour query, with substantially incorrect EXPLAIN. I don't claim to have any/all of the answers myself, but this needs attention very badly. -- Simon Riggs www.2ndQuadrant.com PostgreSQL Training, Services and Support