X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by postgresql.org (Postfix) with ESMTP id 9A7E711F6600 for ; Fri, 7 Apr 2006 17:24:21 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 34745-05 for ; Fri, 7 Apr 2006 17:24:17 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey- Received: from exchange.g2switchworks.com (mail.g2switchworks.com [63.87.162.25]) by postgresql.org (Postfix) with ESMTP id CA16411F61E0 for ; Fri, 7 Apr 2006 17:24:18 -0300 (ADT) Received: from 10.10.1.37 ([10.10.1.37]) by exchange.g2switchworks.com ([10.10.1.2]) with Microsoft Exchange Server HTTP-DAV ; Fri, 7 Apr 2006 20:24:18 +0000 Received: from state.g2switchworks.com by mail.g2switchworks.com; 07 Apr 2006 15:24:18 -0500 Subject: Re: pg 8.1.3, AIX, huge box, painfully slow. From: Scott Marlowe To: Gavin Hamill Cc: pgsql-performance@postgresql.org In-Reply-To: <20060407205919.a091da26.gdh@laterooms.com> References: <20060407185823.abe93017.gdh@laterooms.com> <1144436060.32269.13.camel@state.g2switchworks.com> <20060407205919.a091da26.gdh@laterooms.com> Content-Type: text/plain Content-Transfer-Encoding: 7bit Message-Id: <1144441457.32269.29.camel@state.g2switchworks.com> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 (1.4.6-2) Date: Fri, 07 Apr 2006 15:24:18 -0500 X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0.1 required=5 tests=[AWL=0.099, UNPARSEABLE_RELAY=0.001] X-Spam-Score: 0.1 X-Spam-Level: X-Archive-Number: 200604/153 X-Sequence-Number: 18237 On Fri, 2006-04-07 at 14:59, Gavin Hamill wrote: > On Fri, 07 Apr 2006 13:54:21 -0500 > Scott Marlowe wrote: > > > Are the same queries getting the same basic execution plan on both > > boxes? Turn on logging for slow queries, and explain analyze them on > > both machines to see if they are. > > See reply to Tom Lane :) I didn't see one go by yet... Could be sitting in the queue. > They probably would if this had been bought new - as it is, we have > rented the machine for a month from a 2nd-user dealer to see if it's > capable of taking the load. I'm now glad we did this. Thank god. I had a picture of you sitting on top of a brand new very expensive pSeries Let us know if changing the fsync setting helps. Hopefully that's all the problem is. Off on a tangent. If the aggregate memory bandwidth of the pSeries is no greater than you Xeon you might not see a big improvement if you were memory bound before. If you were CPU bound, you may or may not see an improvement. Can you describe the disc subsystems in the two machines for us? What kind of read / write load you have? It could be the older box was running on IDE drives with fake fsync responses which would lie, be fast, but not reliable in case of a power outage. Do you have hardware RAID for your pSeries? how many discs, how much battery backed cache, etc? > Multi-Opteron was the other thing we considered but decided to give > 'Big Iron' UNIX a whirl... It still might be a good choice, if it's a simple misconfiguration issue. But man, those new multiple core opterons can make some impressive machines for very little money.