Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.84_2) (envelope-from ) id 1b7nyE-00077s-Rs for pgsql-hackers@arkaria.postgresql.org; Tue, 31 May 2016 18:00:50 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.84_2) (envelope-from ) id 1b7nyE-0005PR-Ea for pgsql-hackers@arkaria.postgresql.org; Tue, 31 May 2016 18:00:50 +0000 Received: from makus.postgresql.org ([2001:4800:1501:1::229]) by malur.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1b7nyA-0005In-FG for pgsql-hackers@postgresql.org; Tue, 31 May 2016 18:00:46 +0000 Received: from sss.pgh.pa.us ([66.207.139.130]) by makus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1b7ny7-00041j-VK for pgsql-hackers@postgresql.org; Tue, 31 May 2016 18:00:45 +0000 Received: from sss1.sss.pgh.pa.us (localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.4/8.14.4) with ESMTP id u4VI0Puv021147; Tue, 31 May 2016 14:00:25 -0400 From: Tom Lane To: Josh berkus cc: Peter Geoghegan , Robert Haas , Noah Misch , David Rowley , Amit Kapila , Alvaro Herrera , Magnus Hagander , Bruce Momjian , PostgreSQL-development Subject: Re: Rename max_parallel_degree? In-reply-to: <9816.1464715836@sss.pgh.pa.us> References: <20160426152217.GA548975@alvherre.pgsql> <20160529053300.GD496776@tornado.leadboat.com> <574DBEA4.9000205@agliodbs.com> <8716.1464714201@sss.pgh.pa.us> <574DC585.7010507@agliodbs.com> <574DC881.5010006@agliodbs.com> <9816.14647! 15836@sss.pgh.pa.us> Comments: In-reply-to Tom Lane message dated "Tue, 31 May 2016 13:30:36 -0400" MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="----- =_aaaaaaaaaa0" Content-ID: <21111.1464717588.0@sss.pgh.pa.us> Date: Tue, 31 May 2016 14:00:25 -0400 Message-ID: <21146.1464717625@sss.pgh.pa.us> X-Pg-Spam-Score: -3.3 (---) List-Archive: List-Help: List-ID: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: X-Mailing-List: pgsql-hackers Precedence: bulk Sender: pgsql-hackers-owner@postgresql.org ------- =_aaaaaaaaaa0 Content-Type: text/plain; charset="us-ascii" Content-ID: <21111.1464717588.1@sss.pgh.pa.us> I wrote: > I really think that a GUC named "max_parallel_workers", which in fact > limits the number of workers and not something else, is the way to go. To be concrete, I suggest comparing the attached documentation patch with Robert's. Which one is more understandable? (I have not bothered preparing code changes to go with this, but am willing to do so.) regards, tom lane ------- =_aaaaaaaaaa0 Content-Type: text/x-diff; name="rename-max-parallel-degree-docs-only.patch"; charset="us-ascii" Content-ID: <21111.1464717588.2@sss.pgh.pa.us> Content-Description: rename-max-parallel-degree-docs-only.patch Content-Transfer-Encoding: quoted-printable diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index 72b5920..fccde28 100644 *** a/doc/src/sgml/config.sgml --- b/doc/src/sgml/config.sgml *************** include_dir 'conf.d' *** 1998,2019 **** =20=20 ! ! max_parallel_degree (integer) ! max_parallel_degree configuration parameter<= /primary> ! Sets the maximum number of workers that can be started for an ! individual parallel operation. Parallel workers are taken from = the ! pool of processes established by ! . Note that the requ= ested ! number of workers may not actually be available at runtime. If = this ! occurs, the plan will run with fewer workers than expected, whic= h may ! be inefficient. The default value is 2. Setting this value to 0 ! disables parallel query execution. --- 1998,2020 ---- =20=20 ! ! max_parallel_workers (integer) ! max_parallel_workers configuration parameter= ! Sets the maximum number of worker processes that can be used to ! assist an individual parallelizable operation. Parallel workers= are ! taken from the cluster-wide pool of processes established by ! . Depending on the s= ize of ! the pool and the number of other parallel queries active, the ! requested number of workers may not actually be available at run= time. ! If this occurs, the plan will run with fewer workers than expect= ed, ! which may be inefficient. The default value is 2. Setting this ! value to 0 disables parallel query execution. diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_t= able.sgml index d1807ed..d73cf39 100644 *** a/doc/src/sgml/ref/create_table.sgml --- b/doc/src/sgml/ref/create_table.sgml *************** CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY=20 *** 909,922 **** =20=20 ! parallel_degree (integer) ! The parallel degree for a table is the number of workers that should ! be used to assist a parallel scan of that table. If not set, the ! system will determine a value based on the relation size. The actu= al ! number of workers chosen by the planner may be less, for example du= e to ! the setting of . --- 909,923 ---- =20=20 ! parallel_workers (integer) ! This setting limits the number of parallel worker processes that sh= ould ! be used to assist a parallel scan of this table. If not set, the ! planner will select a value based on the relation size. The actual ! number of workers chosen by the planner may be less, for example ! because it is also constrained by ! ; it will not be more. diff --git a/doc/src/sgml/release-9.6.sgml b/doc/src/sgml/release-9.6.sgml index 38e1967..3d78b00 100644 *** a/doc/src/sgml/release-9.6.sgml --- b/doc/src/sgml/release-9.6.sgml *************** *** 153,159 **** Use of parallel query execution can be controlled through the new configuration parameters ! , , , and . --- 153,159 ---- Use of parallel query execution can be controlled through the new configuration parameters ! , , , and . ------- =_aaaaaaaaaa0 Content-Type: text/plain Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers ------- =_aaaaaaaaaa0--