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 1pYbBs-0008Q0-Sj for pgsql-hackers@arkaria.postgresql.org; Sat, 04 Mar 2023 23:21:24 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.92) (envelope-from ) id 1pYbBr-00043I-14 for pgsql-hackers@arkaria.postgresql.org; Sat, 04 Mar 2023 23:21:23 +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 1pYbBq-000439-Ez for pgsql-hackers@lists.postgresql.org; Sat, 04 Mar 2023 23:21:22 +0000 Received: from sss.pgh.pa.us ([66.207.139.130]) by makus.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1pYbBj-0005so-RL for pgsql-hackers@postgresql.org; Sat, 04 Mar 2023 23:21:21 +0000 Received: from sss1.sss.pgh.pa.us (localhost [127.0.0.1]) by sss.pgh.pa.us (8.15.2/8.15.2) with ESMTP id 324NL92f3039229; Sat, 4 Mar 2023 18:21:09 -0500 From: Tom Lane To: Andres Freund cc: Kyotaro Horiguchi , melanieplageman@gmail.com, vignesh21@gmail.com, pryzby@telsasoft.com, lukas@fittl.com, alvherre@alvh.no-ip.org, magnus@hagander.net, pgsql-hackers@postgresql.org, thomas.munro@gmail.com, m.sakrejda@gmail.com Subject: Re: pg_stat_bgwriter.buffers_backend is pretty meaningless (and more?) In-reply-to: <20230211182437.ype5tk3awen2htvw@awork3.anarazel.de> References: <20230124.172203.448918351330829200.horikyota.ntt@gmail.com> <20230124223512.xqp7tjgqvzqokaxq@awork3.anarazel.de> <20230125.165617.724951472557617342.horikyota.ntt@gmail.com> <20230208063814.boyh5ibydbfuo2uk@awork3.anarazel.de> <20230209050319.chyyup4vtq4jzobq@awork3.anarazel.de> <20230211182437.ype5tk3awen2htvw@awork3.anarazel.de> Comments: In-reply-to Andres Freund message dated "Sat, 11 Feb 2023 10:24:37 -0800" MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <3039227.1677972069.1@sss.pgh.pa.us> Content-Transfer-Encoding: quoted-printable Date: Sat, 04 Mar 2023 18:21:09 -0500 Message-ID: <3039228.1677972069@sss.pgh.pa.us> List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Archived-At: Precedence: bulk Andres Freund writes: > Just pushed the actual pg_stat_io view, the splitting of the tablespace = test, > and the pg_stat_io tests. One of the test cases is flapping a bit: diff -U3 /home/pg/build-farm-15/buildroot/HEAD/pgsql.build/src/test/regres= s/expected/stats.out /home/pg/build-farm-15/buildroot/HEAD/pgsql.build/src= /test/regress/results/stats.out --- /home/pg/build-farm-15/buildroot/HEAD/pgsql.build/src/test/regress/exp= ected/stats.out 2023-03-04 21:30:05.891579466 +0100 +++ /home/pg/build-farm-15/buildroot/HEAD/pgsql.build/src/test/regress/res= ults/stats.out 2023-03-04 21:34:26.745552661 +0100 @@ -1201,7 +1201,7 @@ SELECT :io_sum_shared_after_reads > :io_sum_shared_before_reads; ?column? = ---------- - t + f (1 row) = DROP TABLE test_io_shared; There are two instances of this today [1][2], and I've seen it before but failed to note down where. regards, tom lane [1] https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=3Dgrison&dt=3D= 2023-03-04%2021%3A19%3A39 [2] https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=3Dmule&dt=3D20= 23-03-04%2020%3A30%3A05