Received: from makus.postgresql.org ([98.129.198.125]) by malur.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1TDN9B-0001G2-Gn for pgsql-docs@postgresql.org; Sun, 16 Sep 2012 22:17:01 +0000 Received: from sss.pgh.pa.us ([66.207.139.130]) by makus.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1TDN99-0001zy-QK for pgsql-docs@postgresql.org; Sun, 16 Sep 2012 22:17:00 +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 q8GMGtct028911; Sun, 16 Sep 2012 18:16:55 -0400 (EDT) From: Tom Lane To: Jeff Janes cc: pgsql-docs@postgresql.org, Bill Martin Subject: Re: [PERFORM] Planner selects different execution plans depending on limit In-reply-to: References: <5051F227.7090600@krogh.cc> <26906.1347548059@sss.pgh.pa.us> <16905.1347557599@sss.pgh.pa.us> Comments: In-reply-to Jeff Janes message dated "Sun, 16 Sep 2012 14:39:34 -0700" Date: Sun, 16 Sep 2012 18:16:55 -0400 Message-ID: <28910.1347833815@sss.pgh.pa.us> X-Pg-Spam-Score: -2.4 (--) X-Archive-Number: 201209/13 X-Sequence-Number: 7465 Jeff Janes writes: > On Thu, Sep 13, 2012 at 10:33 AM, Tom Lane wrote: >> Just pretend it's a table. >> ALTER TABLE index_name ALTER COLUMN column_name SET STATISTICS ... >> >> You'll need to look at the index (eg with \d) to see what the name of >> the desired column is, since index expressions have system-assigned >> column names. > Is this documented anywhere? I couldn't find it. If not, which > section would be the best one to add it to? It's not documented, mainly because it hasn't reached the level of being a supported feature. I'd like to figure out how to get pg_dump to dump such settings before we call it supported. (The stumbling block is exactly that index column names aren't set in stone, so it's not clear that the ALTER command would do the right thing on dump-and-reload.) regards, tom lane