Received: from localhost (unknown [200.46.204.183]) by mail.postgresql.org (Postfix) with ESMTP id 35BBD65006C for ; Thu, 6 Nov 2008 18:05:24 -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 55933-06 for ; Thu, 6 Nov 2008 18:05:23 -0400 (AST) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from wa-out-1112.google.com (wa-out-1112.google.com [209.85.146.182]) by mail.postgresql.org (Postfix) with ESMTP id 8A16464FF9A for ; Thu, 6 Nov 2008 18:05:23 -0400 (AST) Received: by wa-out-1112.google.com with SMTP id j4so449908wah.19 for ; Thu, 06 Nov 2008 14:05:21 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to :subject:cc:in-reply-to:mime-version:content-type :content-transfer-encoding:content-disposition:references; bh=c5rnvMT7P4pzsWG9gj7b1NX3xlUBrSvPEQOznd8CQOU=; b=J1IbfMqyZ7hVuszfSt0IGBOu7gEwF/GsOUUW+irV4i8S+Gyh5aIbo8QupeclIeG/0q Y7uXEet1MKFyiKa/2CVQz5OGCfH7K7CRmjMbFlwzC2KtB3iMsnIRD1UnCRqRPcqJTrP0 qMVZ3qVy/X7uIVluZV0v48WQGNBiYrZSvwZLE= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=blHcarqQoYKWj1ifREJJrLDK/AhSCfpQel/+Mb+frj200y5117ADfaMcGkk8am9L7J gsnNpXYnYrI4YNmLpJx1Ubw7kFAMCscBH4mmmwfgcQDO0lMn6lAuUDC11v16ggeTMuMl tfv8foH02Py0VzKJVuiibnJxtoBBjvG/MwXc4= Received: by 10.114.146.6 with SMTP id t6mr1029148wad.220.1226009121672; Thu, 06 Nov 2008 14:05:21 -0800 (PST) Received: by 10.114.39.11 with HTTP; Thu, 6 Nov 2008 14:05:21 -0800 (PST) Message-ID: Date: Thu, 6 Nov 2008 15:05:21 -0700 From: "Scott Marlowe" To: "Scott Carey" Subject: Re: Create and drop temp table in 8.3.4 Cc: "Kevin Grittner" , jd@commandprompt.com, pgsql-performance@postgresql.org In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <4911957A.EE98.0025.0@wicourts.gov> <4911D4DB.EE98.0025.0@wicourts.gov> <4912EAFF.EE98.0025.0@wicourts.gov> <1225999071.1204.14.camel@jd-laptop.pragmaticzealot.org> <4912F29E.EE98.0025.0@wicourts.gov> X-Archive-Number: 200811/39 X-Sequence-Number: 31770 On Thu, Nov 6, 2008 at 2:05 PM, Scott Carey wrote: > To others that may stumble upon this thread: > Note that Write Barriers can be very important for data integrity when power > loss or hardware failure are a concern. Only disable them if you know the > consequences are mitigated by other factors (such as a BBU + db using the > WAL log with sync writes), or if you accept the additional risk to data > loss. Also note that LVM prevents the possibility of using write barriers, > and lowers data reliability as a result. The consequences are application > dependent and also highly file system dependent. I am pretty sure that with no write barriers that even a BBU hardware caching raid controller cannot guarantee your data.