Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1UMSzk-0006qf-LY for pgsql-performance@arkaria.postgresql.org; Mon, 01 Apr 2013 00:53:08 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.72) (envelope-from ) id 1UMSzk-00023p-4S for pgsql-performance@arkaria.postgresql.org; Mon, 01 Apr 2013 00:53:08 +0000 Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29]) by malur.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1UMSzj-00023j-5h for pgsql-performance@postgresql.org; Mon, 01 Apr 2013 00:53:07 +0000 Received: from sss.pgh.pa.us ([66.207.139.130]) by magus.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1UMSzd-00040c-EG for pgsql-performance@postgresql.org; Mon, 01 Apr 2013 00:53:06 +0000 Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.5/8.14.5) with ESMTP id r310qxQj024672; Sun, 31 Mar 2013 20:52:59 -0400 (EDT) From: Tom Lane To: pg noob cc: pgsql-performance Subject: Re: query plan estimate In-reply-to: References: Comments: In-reply-to pg noob message dated "Mon, 25 Mar 2013 14:16:51 -0400" Date: Sun, 31 Mar 2013 20:52:59 -0400 Message-ID: <24671.1364777579@sss.pgh.pa.us> X-Pg-Spam-Score: -4.2 (----) List-Archive: List-Help: List-ID: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: X-Mailing-List: pgsql-performance Precedence: bulk Sender: pgsql-performance-owner@postgresql.org pg noob writes: > I'm looking at this query plan, an excerpt of which is shown here, and I am > just wondering how the estimated cost for the Nested Loop is calculated? http://www.postgresql.org/docs/9.2/static/using-explain.html There's a nestloop example about a third of the way down the page ... regards, tom lane -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance