Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.89) (envelope-from ) id 1f6O3y-0003eH-4u for pgsql-hackers@arkaria.postgresql.org; Wed, 11 Apr 2018 22:17:58 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.89) (envelope-from ) id 1f6O3w-0007yf-Sy for pgsql-hackers@arkaria.postgresql.org; Wed, 11 Apr 2018 22:17:56 +0000 Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29]) by malur.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.89) (envelope-from ) id 1f6O16-0000f1-39 for pgsql-hackers@lists.postgresql.org; Wed, 11 Apr 2018 22:15:00 +0000 Received: from hook.sigaev.ru ([93.180.27.50]) by magus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.89) (envelope-from ) id 1f6O12-0004VA-6f for pgsql-hackers@postgresql.org; Wed, 11 Apr 2018 22:14:59 +0000 Received: from zorg.sigaev.ru (95-25-2-27.broadband.corbina.ru [95.25.2.27]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: teodor) by hook.sigaev.ru (Postfix) with ESMTPSA id A3B4FB191BE; Thu, 12 Apr 2018 01:14:54 +0300 (MSK) Subject: Re: Partitioned tables and covering indexes To: Peter Eisentraut , Peter Geoghegan Cc: Alexander Korotkov , Alvaro Herrera , Amit Langote , Jaime Casanova , Pg Hackers References: <13123421-1d52-d0e4-c95c-6d69011e0595@sigaev.ru> <20180411194753.vhnwqss2hgqtao6v@alvherre.pgsql> <352da91b-caeb-bbd9-cfe5-f477ad2628be@2ndquadrant.com> <641a91aa-19ef-e092-dd4c-2554487169fc@2ndquadrant.com> From: Teodor Sigaev Message-ID: <07465162-72d9-e192-bedb-6e37bca50b56@sigaev.ru> Date: Thu, 12 Apr 2018 01:14:54 +0300 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:52.0) Gecko/20100101 Firefox/52.0 SeaMonkey/2.49.2 MIME-Version: 1.0 In-Reply-To: <641a91aa-19ef-e092-dd4c-2554487169fc@2ndquadrant.com> Content-Type: text/plain; charset=KOI8-R; format=flowed Content-Transfer-Encoding: 7bit List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Precedence: bulk >> That's the idea that I tried to express. The point is that we need to >> tell the user that there is no need to worry about it, rather than >> that they're wrong to ask about it. Though we should probably actually >> just throw an error. > > Or maybe it should be the collation of the underlying table columns. > Otherwise the collation returned by an index-only scan would be > different from a table scan, no? +1, dangerous -- Teodor Sigaev E-mail: teodor@sigaev.ru WWW: http://www.sigaev.ru/