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 1nfMjo-000377-RN for pgsql-hackers@arkaria.postgresql.org; Fri, 15 Apr 2022 14:15:52 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.92) (envelope-from ) id 1nfMjl-0005gb-Ek for pgsql-hackers@arkaria.postgresql.org; Fri, 15 Apr 2022 14:15:49 +0000 Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29]) by malur.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nfMjl-0005gR-5J for pgsql-hackers@lists.postgresql.org; Fri, 15 Apr 2022 14:15:49 +0000 Received: from sss.pgh.pa.us ([66.207.139.130]) by magus.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nfMjd-0000wu-HW for pgsql-hackers@lists.postgresql.org; Fri, 15 Apr 2022 14:15:45 +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 23FEFWvm1637672; Fri, 15 Apr 2022 10:15:32 -0400 From: Tom Lane To: Andres Freund cc: Noah Misch , Peter Geoghegan , David Rowley , PostgreSQL Hackers Subject: Re: Intermittent buildfarm failures on wrasse In-reply-to: <20220415052125.GD862547@rfd.leadboat.com> References: <1521388.1649953580@sss.pgh.pa.us> <1547912.1649971995@sss.pgh.pa.us> <1553951.1649975018@sss.pgh.pa.us> <1570894.1649986347@sss.pgh.pa.us> <20220415015249.kfsqxujrf2bn2wz6@alap3.anarazel.de> <20220415024515.GA862547@rfd.leadboat.com> <20220415051205.6abhlilh6fnjgohr@alap3.anarazel.de> <20220415052125.GD862547@rfd.leadboat.com> Comments: In-reply-to Noah Misch message dated "Thu, 14 Apr 2022 22:21:25 -0700" MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <1637670.1650032132.1@sss.pgh.pa.us> Content-Transfer-Encoding: quoted-printable Date: Fri, 15 Apr 2022 10:15:32 -0400 Message-ID: <1637671.1650032132@sss.pgh.pa.us> List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Archived-At: Precedence: bulk The morning's first result is that during a failing run, the vacuum in test_setup sees 2022-04-15 16:01:43.064 CEST [4436:75] pg_regress/test_setup LOG: stateme= nt: VACUUM ANALYZE tenk1; = 2022-04-15 16:01:43.064 CEST [4436:76] pg_regress/test_setup LOG: vacuumi= ng "regression.public.tenk1" = 2022-04-15 16:01:43.064 CEST [4436:77] pg_regress/test_setup STATEMENT: V= ACUUM ANALYZE tenk1; = 2022-04-15 16:01:43.071 CEST [4436:78] pg_regress/test_setup LOG: finishe= d vacuuming "regression.public.tenk1": index scans: 0 pages: 0 removed, 345 remain, 345 scanned (100.00% of total) = = tuples: 0 removed, 10000 remain, 0 are dead but not yet removable = = removable cutoff: 724, older by 26 xids when operation ended index scan not needed: 0 pages from table (0.00% of total) had 0 d= ead item identifiers removed avg read rate: 2.189 MB/s, avg write rate: 2.189 MB/s buffer usage: 695 hits, 2 misses, 2 dirtied WAL usage: 1 records, 0 full page images, 188 bytes system usage: CPU: user: 0.00 s, system: 0.00 s, elapsed: 0.00 s 2022-04-15 16:01:43.071 CEST [4436:79] pg_regress/test_setup STATEMENT: V= ACUUM ANALYZE tenk1; OldestXmin =3D 724 is too old to consider tenk1's contents as all-visible: regression=3D# select distinct xmin from tenk1; xmin = ------ 749 (1 row) In fact, right after initdb pg_controldata shows Latest checkpoint's NextXID: 0:724 Latest checkpoint's oldestXID: 716 So there's no longer any doubt that something is holding back OldestXmin. I will go put some instrumentation into the code that's computing that. regards, tom lane