Not sure if you noticed, but piculet has twice failed the
007_standby_source.pl test that was added by 9c4f5192f:
https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=piculet&dt=2020-11-15%2006%3A00%3A11
https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=piculet&dt=2020-11-13%2011%3A20%3A10
and francolin failed once:
https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=francolin&dt=2020-11-12%2018%3A57%3A33
These failures look the same:
# Failed test 'table content after rewind and insert: query result matches'
# at t/007_standby_source.pl line 160.
# got: 'in A
# in A, before promotion
# in A, after C was promoted
# '
# expected: 'in A
# in A, before promotion
# in A, after C was promoted
# in A, after rewind
# '
# Looks like you failed 1 test of 3.
[11:27:01] t/007_standby_source.pl ...
Dubious, test returned 1 (wstat 256, 0x100)
Failed 1/3 subtests
Now, I'm not sure what to make of that, but I can't help noticing that
piculet uses --disable-atomics while francolin uses --disable-spinlocks.
That leads the mind towards some kind of low-level synchronization
bug ...
regards, tom lane