Received: from localhost (maia-3.hub.org [200.46.204.184]) by postgresql.org (Postfix) with ESMTP id 068C79FB6CD for ; Wed, 18 Jul 2007 06:04:03 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.184]) (amavisd-maia, port 10024) with ESMTP id 27808-04 for ; Wed, 18 Jul 2007 06:03:53 -0300 (ADT) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.5 Received: from ug-out-1314.google.com (ug-out-1314.google.com [66.249.92.169]) by postgresql.org (Postfix) with ESMTP id D62619FB6B5 for ; Wed, 18 Jul 2007 06:03:57 -0300 (ADT) Received: by ug-out-1314.google.com with SMTP id a2so265653ugf for ; Wed, 18 Jul 2007 02:03:56 -0700 (PDT) DKIM-Signature: a=rsa-sha1; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:user-agent:mime-version:to:cc:subject:references:in-reply-to:content-type:content-transfer-encoding:sender; b=iG2uxTz8RS1llIDDIS43wWGhUrRZnWEKunHAXJ1DzGcnJvTneRSXLYA9zDaR7WNLkpOOg11leiHlfoymv51a3vN713bRMuorOKEoOXVuoDDncng45YTgqaWNbHvkmTotlZH+cCDEgEehudC19G7HlFTBvh8zqVF9dKbf6v/Zot8= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:user-agent:mime-version:to:cc:subject:references:in-reply-to:content-type:content-transfer-encoding:sender; b=NWaXmcMp8xrN4P1HQZp5sDuYSUaYEApF4w2qAf3hE6Z/VjiL7/rPqsHw0+Lkyx+t2MgeIkwtzmWu9srnNg1dLIgdKHC+DpflU3JOfmHSenyBF3njy4BpKMdS+VGlKacs3z3IBO+c7TIkWnh0g6WGLKboFTOBNyb1VcplYxxfHB4= Received: by 10.66.243.4 with SMTP id q4mr199806ugh.1184749435993; Wed, 18 Jul 2007 02:03:55 -0700 (PDT) Received: from ?192.168.1.33? ( [82.20.57.141]) by mx.google.com with ESMTPS id l20sm2299564uga.2007.07.18.02.03.54 (version=SSLv3 cipher=RC4-MD5); Wed, 18 Jul 2007 02:03:55 -0700 (PDT) Message-ID: <469DD744.1060906@enterprisedb.com> Date: Wed, 18 Jul 2007 10:03:00 +0100 From: Heikki Linnakangas User-Agent: Icedove 1.5.0.10 (X11/20070329) MIME-Version: 1.0 To: Ron Mayer CC: pgsql-performance@postgresql.org Subject: Re: ionice to make vacuum friendier? References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200707/208 X-Sequence-Number: 25892 Ron Mayer wrote: > Seems Linux has IO scheduling through a program called ionice. > > Has anyone here experimented with using it rather than > vacuum sleep settings? I looked at that briefly for smoothing checkpoints, but it was unsuitable for that purpose because it only prioritizes reads, not writes. It maybe worth trying for vacuum, though vacuum too can do a lot of writes. In the worst case, the OS cache is saturated with dirty pages, which blocks all writes in the system. If it did prioritize writes as well, that would be *excellent*. Any kernel hackers out there looking for a project? -- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com