Received: from localhost (unknown [200.46.208.211]) by mail.postgresql.org (Postfix) with ESMTP id 02B28633751 for ; Thu, 7 Jan 2010 21:40:28 -0400 (AST) Received: from mail.postgresql.org ([200.46.204.86]) by localhost (mx1.hub.org [200.46.208.211]) (amavisd-maia, port 10024) with ESMTP id 81470-07 for ; Fri, 8 Jan 2010 01:40:09 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mail-ew0-f226.google.com (mail-ew0-f226.google.com [209.85.219.226]) by mail.postgresql.org (Postfix) with ESMTP id 1F4D1632C85 for ; Thu, 7 Jan 2010 21:40:16 -0400 (AST) Received: by ewy26 with SMTP id 26so17348744ewy.3 for ; Thu, 07 Jan 2010 17:40:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:cc:content-type; bh=U/uBq2pbcymMaOT5D6JC+empUFy5UuwUr/yvy7wtHtc=; b=fvmYDOvsS5eWFJBXtMuP6u9L+8SlnB6cTmh/3/YX9z4NTL46jIQDsdo2kiEoT97NfN wgR7+IePLa2IIZFo6I4Be1c1RHk1x7qMXaIlHC9NQj3OmFyjw7xuh8t5YMlLPmo/zUx1 dbrIpFaN2+WpiCpLRjyIZ0D/O8eDC473B9s6s= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=SosVIK3e6nO1BH7YZZZWlAJzwoMKbSmipHMkjHydoM7FAtgkQVSn1kbND0XD5rUlUs ZsEy3qDJHsR4jh9USDdCMyOnZZkxw8eKTYOryjm2dx2+dFgvsH+fhpqM/At6lDLidyHB Akf9p9NAVMU/XwlrLS08aPsQ7XKYRaCNBWPAE= MIME-Version: 1.0 Received: by 10.216.87.81 with SMTP id x59mr490825wee.147.1262914814628; Thu, 07 Jan 2010 17:40:14 -0800 (PST) In-Reply-To: References: Date: Thu, 7 Jan 2010 18:40:14 -0700 Message-ID: Subject: Re: Massive table (500M rows) update nightmare From: Scott Marlowe To: Carlo Stonebanks Cc: pgsql-performance@postgresql.org Content-Type: text/plain; charset=ISO-8859-1 X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.56 tagged_above=-10 required=5 tests=AWL=-0.820, BAYES_20=-0.74 X-Spam-Level: X-Archive-Number: 201001/130 X-Sequence-Number: 37010 On Thu, Jan 7, 2010 at 2:48 PM, Carlo Stonebanks wrote: > Doing the updates in smaller chunks resolved these apparent freezes - or, > more specifically, when the application DID freeze, it didn't do it for more > than 30 seconds. In all likelyhood, this is the OS and the DB thrashing. It might well be checkpoints. Have you tried cranking up checkpoint segments to something like 100 or more and seeing how it behaves then?