Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1UceYD-0006L3-0o for pgsql-performance@arkaria.postgresql.org; Wed, 15 May 2013 16:27:38 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.72) (envelope-from ) id 1UceYC-0003FG-Ax for pgsql-performance@arkaria.postgresql.org; Wed, 15 May 2013 16:27:36 +0000 Received: from makus.postgresql.org ([2001:4800:7903:4::125]) by malur.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1UceYB-0003FA-7B for pgsql-performance@postgresql.org; Wed, 15 May 2013 16:27:35 +0000 Received: from smtp2.peak6.com ([38.98.137.9]) by makus.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1UceY8-0007Mj-4Z for pgsql-performance@postgresql.org; Wed, 15 May 2013 16:27:34 +0000 X-AuditID: 0a02cb20-b7f886d000007309-ca-5193b7738485 Received: from sswchi5pcas1.peak6.net (Unknown_Domain [10.100.13.22]) by smtp2.peak6.com (Symantec Messaging Gateway) with SMTP id 3F.0D.29449.377B3915; Wed, 15 May 2013 11:27:31 -0500 (CDT) Received: from [10.10.201.64] (10.10.201.64) by sswchi5pcas1.peak6.net (10.100.13.25) with Microsoft SMTP Server (TLS) id 14.2.247.3; Wed, 15 May 2013 11:27:30 -0500 Message-ID: <5193B771.70502@optionshouse.com> Date: Wed, 15 May 2013 11:27:29 -0500 From: Shaun Thomas Reply-To: Organization: Peak6 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130329 Thunderbird/17.0.5 MIME-Version: 1.0 To: Heikki Linnakangas CC: "pgsql-performance@postgresql.org" Subject: Re: Thinking About Correlated Columns (again) References: <5193AA62.2040700@optionshouse.com> <5193AF36.3040409@vmware.com> In-Reply-To: <5193AF36.3040409@vmware.com> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed content-transfer-encoding: 7bit X-Originating-IP: [10.10.201.64] X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFupnleLIzCtJLcpLzFFi42LhSuEV0y3ePjnQ4PteaYspV3Itrs88x+zA 5HFh3zR2j3fz37IFMEU1MNok5uXllySWpCqkpBYn2yr5F5Rk5ucVe+SXFqcquGQWJ+ckZuam FikpZKbYKhkrKRTkJCan5qbmldgqJRYUpOalKNlxKWAAG6CyzDyF1Lzk/JTMvHRbJc9gf10L C1NLXUMlu3hkkNDJkjFv/2vGglUsFe+fX2drYNzD3MXIySEhYCJxe/MZVghbTOLCvfVsXYxc HEICBxglFr7dwQ7hrGSUOHVoOiNIFa+ArsTBjnNgNouAqsSBw03sIDYbUHxS/wo2EFtIQEWi 7+wNJhCbX0BYYt+HJrBtogJhEqvWL2OGmCMocXLmExYQW0TAQOLC+wlgcWYBT4mOU6vA5gsL OEjMW36LEWKmr8SbOxA3cApoSXQsPs8EUW8rcWHOdRYIW15i+9s5zBD1qhIrmieyQXymIPH/ yjumCYwis5CsnoWkfRaS9gWMzKsYxYvLEpMzMs0KinNLCoz0ClITs8308lJLNjGCYp3ptMIO xs09VocYBTgYlXh4PyyaHCjEmlhWXJl7iFGCg1lJhPfGMqAQb0piZVVqUX58UWlOavEhRh9g mE1klhJNzgemobySeENjUwNTS1NDU3NTQyMcwkrivLMuNQUKCaQD0092ampBahHMOCYOTqkG xo6FJ3ok+I4e/qW58O6SGjebPF6Pxp4ZPq190zbES300rFy48RDX1ye5gtdDe/93lW/5Krnq y6LHTa/nH+IQj95WyKv3PZ37Yu+b65YL9fd5OJ7RVNy+wDfuwazzE+YEs141vKptsmDPVJPU hpTcAu+7Ux55RPhKMa6/0n9BfcbufwxvLJwttZRYijMSDbWYi4oTAd6n96EiAwAA X-Pg-Spam-Score: 0.8 (/) 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 On 05/15/2013 10:52 AM, Heikki Linnakangas wrote: > I think it would be pretty straightforward to use such a statistic, > once we have it. So perhaps we should get started by allowing the DBA > to set a correlation metric manually, and use that in the planner. The planner already kinda does this with functional indexes. It would definitely be nice to override the stats with known correlations when possible. -- Shaun Thomas OptionsHouse | 141 W. Jackson Blvd. | Suite 500 | Chicago IL, 60604 312-676-8870 sthomas@optionshouse.com ______________________________________________ See http://www.peak6.com/email_disclaimer/ for terms and conditions related to this email -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance