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 1hQXLV-0000D1-A0 for pgsql-advocacy@arkaria.postgresql.org; Tue, 14 May 2019 13:19:53 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.89) (envelope-from ) id 1hQXLT-0000id-Mh for pgsql-advocacy@arkaria.postgresql.org; Tue, 14 May 2019 13:19:51 +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 1hQXLT-0000iW-FC for pgsql-advocacy@lists.postgresql.org; Tue, 14 May 2019 13:19:51 +0000 Received: from momjian.us ([72.94.173.45]) by magus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1hQXLQ-0005Eq-Un; Tue, 14 May 2019 13:19:51 +0000 Received: from bruce by momjian.us with local (Exim 4.89) (envelope-from ) id 1hQXLN-0000GA-Ve; Tue, 14 May 2019 09:19:45 -0400 Date: Tue, 14 May 2019 09:19:45 -0400 From: Bruce Momjian To: Amit Langote Cc: David Rowley , Justin Clift , "Jonathan S. Katz" , pgsql-advocacy@lists.postgresql.org Subject: Re: PostgreSQL 12: Feature Highlights Message-ID: <20190514131945.6dof67bfzmcftevd@momjian.us> References: <830415f7-78ec-ef7b-0f73-0e810ef87f91@postgresql.org> <3ea29ec1-38e9-b5bd-571e-8d1f85175c5a@lab.ntt.co.jp> <20190514025918.mqfedp3k625t5eoc@momjian.us> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Precedence: bulk On Tue, May 14, 2019 at 06:25:43PM +0900, Amit Langote wrote: > Considering the quoted discussion here, maybe it's a good idea to note > that only the operations that need to touch a small number of partitions > are now processed efficiently, which covers both SELECT/UPDATE/DELETE that > benefit from improved pruning efficiency and INSERT that benefit from > improved tuple routing efficiency. So, maybe: > > Tables with thousands of child partitions can now be processed > efficiently by operations that only need to touch a small number > of partitions. > > That is, as I mentioned above, as opposed to queries that need to process > all partitions (such as, select count(*) from partitioned_table), which > don't perform any faster in v12 than in v11. The percentage of users who > run such workloads on PostgreSQL may be much smaller today, but perhaps > it's not a good idea to mislead them into thinking that *everything* with > partitioned tables is now faster even with thousands of partitions. Agreed, I changed it to your wording. -- Bruce Momjian http://momjian.us EnterpriseDB http://enterprisedb.com + As you are, so once was I. As I am, so you will be. + + Ancient Roman grave inscription +