Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1hTF2k-0005BU-Ve for pgsql-advocacy@arkaria.postgresql.org; Wed, 22 May 2019 00:23:43 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.89) (envelope-from ) id 1hTF2j-00066Y-MW for pgsql-advocacy@arkaria.postgresql.org; Wed, 22 May 2019 00:23:41 +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_SHA1:256) (Exim 4.89) (envelope-from ) id 1hTF2j-00066R-FU for pgsql-advocacy@lists.postgresql.org; Wed, 22 May 2019 00:23:41 +0000 Received: from tama50.ecl.ntt.co.jp ([129.60.39.147]) by magus.postgresql.org with esmtp (Exim 4.89) (envelope-from ) id 1hTF2f-0007rm-8e for pgsql-advocacy@lists.postgresql.org; Wed, 22 May 2019 00:23:41 +0000 Received: from vc2.ecl.ntt.co.jp (vc2.ecl.ntt.co.jp [129.60.86.154]) by tama50.ecl.ntt.co.jp (8.13.8/8.13.8) with ESMTP id x4M0NVQJ010452; Wed, 22 May 2019 09:23:31 +0900 Received: from vc2.ecl.ntt.co.jp (localhost [127.0.0.1]) by vc2.ecl.ntt.co.jp (Postfix) with ESMTP id B4532638607; Wed, 22 May 2019 09:23:31 +0900 (JST) Received: from jcms-pop21.ecl.ntt.co.jp (jcms-pop21.ecl.ntt.co.jp [129.60.87.134]) by vc2.ecl.ntt.co.jp (Postfix) with ESMTP id A8D64638535; Wed, 22 May 2019 09:23:31 +0900 (JST) Received: from [127.0.0.1] (unknown [129.60.241.61]) by jcms-pop21.ecl.ntt.co.jp (Postfix) with ESMTPSA id A28964003B6; Wed, 22 May 2019 09:23:31 +0900 (JST) Subject: Re: PostgreSQL 12: Feature Highlights References: <20190516182628.kbkiajfnlooocgyg@momjian.us> <0cf10a27-c6a0-de4a-cd20-ab7493ea7422@lab.ntt.co.jp> <20190517153653.pmolnulev6imwsn3@momjian.us> <20190518023017.nkucoc5xgoebtvfw@momjian.us> <20190518132031.zjyxgvys7unan53f@momjian.us> <20190521145509.s6bme6pgww3glmku@momjian.us> From: Amit Langote Message-ID: <82a518da-22e5-269f-c350-7caa1d948165@lab.ntt.co.jp> Date: Wed, 22 May 2019 09:23:13 +0900 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190521145509.s6bme6pgww3glmku@momjian.us> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-CC-Mail-RelayStamp: 1 To: Bruce Momjian , David Rowley Cc: "Jonathan S. Katz" , pgsql-advocacy@lists.postgresql.org X-TM-AS-MML: disable List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Precedence: bulk On 2019/05/21 23:55, Bruce Momjian wrote: > On Sun, May 19, 2019 at 02:26:48AM +1200, David Rowley wrote: >> Thanks, typing that up. I think it lacks a bit detail about what's >> actually changed. The change is fairly evident and people can see >> when it takes effect when they look at EXPLAIN and see that the >> Append/MergeAppend node is missing. Also, an Append/MergeAppend may >> exist for inheritance tables and an Append can exist for a simple >> UNION ALL. Both of those cases can have subplans removed to leave only >> a single subplan, to which the additional parallel paths will be >> considered. > > This brings up a few points. First, it seems the change affects > partitioned tables and UNION ALL, which means it probably needs to be > listed in two sections. How about putting this only in E.1.3.1.3. Optimizer? Thanks, Amit