Buildfarm members spurfowl[1] and thorntail[2] have each shown $SUBJECT
once in the past two days. The circumstances are not quite the same;
spurfowl's failure is in autovacuum while thorntail's is in a manual
VACUUM command. Still, it seems clear that there's a recently-introduced
bug here somewhere. I don't see any obvious candidate for the culprit,
though. Any ideas?
regards, tom lane
[1]
https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=spurfowl&dt=2021-04-08%2010%3A22%3A08
[2]
https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=thorntail&dt=2021-04-09%2021%3A28%3A10
