Re: 15beta1 test failure on mips in isolation/expected/stats

Christoph Berg <myon(at)debian(dot)org> writes:
> Debian unstable mips (the old 32-bit one):

> --- /<<PKGBUILDDIR>>/src/test/isolation/expected/stats.out 2022-05-16 21:10:42.000000000 +0000
> +++ /<<PKGBUILDDIR>>/build/src/test/isolation/output_iso/results/stats.out 2022-05-18 23:26:56.573000536 +0000
> @@ -2854,7 +2854,7 @@

> seq_scan|seq_tup_read|n_tup_ins|n_tup_upd|n_tup_del|n_live_tup|n_dead_tup|vacuum_count
> --------+------------+---------+---------+---------+----------+----------+------------
> - 3| 9| 5| 1| 0| 1| 1| 0
> + 3| 9| 5| 1| 0| 4| 1| 0
> (1 row)

I have just discovered that I can reproduce this identical symptom
fairly repeatably on an experimental lashup that I've been running
with bleeding-edge NetBSD on my ancient HPPA box. (You didn't think
I was just going to walk away from that hardware, did you?)

Even more interesting, the repeatability varies with the settings
of max_connections and max_prepared_transactions. At low values
(resp. 20 and 0) I've not been able to make it happen at all, but
at 100 and 2 it happens circa three times out of four.

I have no idea where to start looking, but this is clearly an issue
in the new stats code ... or else the hoped-for goal of removing
flakiness from the stats tests is just as far away as ever.

regards, tom lane