Hi, On 2022-04-15 10:15:32 -0400, Tom Lane wrote: > 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: statement: > VACUUM ANALYZE tenk1; > 2022-04-15 16:01:43.064 CEST [4436:76] pg_regress/test_setup LOG: vacuuming > "regression.public.tenk1" > 2022-04-15 16:01:43.064 CEST [4436:77] pg_regress/test_setup STATEMENT: > VACUUM ANALYZE tenk1; > 2022-04-15 16:01:43.071 CEST [4436:78] pg_regress/test_setup LOG: finished > 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 dead > 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: > VACUUM ANALYZE tenk1;
The horizon advancing by 26 xids during tenk1's vacuum seems like quite a bit, given there's no normal concurrent activity during test_setup. > In fact, right after initdb pg_controldata shows > Latest checkpoint's NextXID: 0:724 > Latest checkpoint's oldestXID: 716 So that's the xmin that e.g. the autovac launcher ends up with during start... If I make get_database_list() sleep for 5s within the scan, I can reproduce on x86-64. Greetings, Andres Freund
