Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jYcdP-000783-KC for pgsql-docs@arkaria.postgresql.org; Tue, 12 May 2020 21:40:19 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.92) (envelope-from ) id 1jYcdN-0004x5-Lm for pgsql-docs@arkaria.postgresql.org; Tue, 12 May 2020 21:40:17 +0000 Received: from makus.postgresql.org ([2001:4800:3e1:1::229]) by malur.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jYcdN-0004wx-G1 for pgsql-docs@lists.postgresql.org; Tue, 12 May 2020 21:40:17 +0000 Received: from momjian.us ([72.94.173.45]) by makus.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jYcdL-00040Y-2d for pgsql-docs@lists.postgresql.org; Tue, 12 May 2020 21:40:16 +0000 Received: from bruce by momjian.us with local (Exim 4.92) (envelope-from ) id 1jYcdK-0005WZ-7T; Tue, 12 May 2020 17:40:14 -0400 Date: Tue, 12 May 2020 17:40:14 -0400 From: Bruce Momjian To: yigongh@gmail.com, pgsql-docs@lists.postgresql.org Subject: Re: The suggestion of reducing autovacuum_vacuum_cost_delay should be documented Message-ID: <20200512214014.GD4666@momjian.us> References: <158927918783.656.11973436145559215458@wrigleys.postgresql.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <158927918783.656.11973436145559215458@wrigleys.postgresql.org> User-Agent: Mutt/1.10.1 (2018-07-13) List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Precedence: bulk On Tue, May 12, 2020 at 10:26:27AM +0000, PG Doc comments form wrote: > The following documentation comment has been logged on the website: > > Page: https://www.postgresql.org/docs/11/runtime-config-autovacuum.html > Description: > > The `autovacuum_vacuum_cost_delay` setting changes to 2ms in PostgreSQL 12 > but in the old Postgresql version, the default setting is still 20ms. I > would suggest adding a suggestion in the old document > to lower the autovacuum_vacuum_cost_delay as: > > > The default value of autovacuum_vacuum_cost_delay is reduced to 2ms in > PostgreSQL 12. Reducing the autovacuum_vacuum_cost_delay will make the > autovacuum more aggressive and might reduce the vacuum cost for > write-intensive workload on big table. Uh, we usually don't suggest new defaults in back branches. -- Bruce Momjian https://momjian.us EnterpriseDB https://enterprisedb.com + As you are, so once was I. As I am, so you will be. + + Ancient Roman grave inscription +