On Mon, Dec 2, 2024 at 11:43 AM Tom Lane <t...@sss.pgh.pa.us> wrote: > Whether that's true or not, it seems like it'd be worth bisecting > to see if we can finger a commit where the behavior changed (and > the same goes for the question of why-isnt-it-an-IOS-scan). However, > the reproducer seems to have quite a low failure probability for me, > which makes it hard to do bisection testing with much confidence. > Can we do anything to make the test more reliable? If I'm right > to suspect autovacuum, maybe triggering lots of manual vacuums > would improve the odds?
I agree that autovacuum (actually, VACUUM) is important here. I find that the test becomes much more reliable if I create the test table "with (autovacuum_analyze_scale_factor=0.99, vacuum_truncate=off)". More importantly, rather than relying on autovacuum, I just run VACUUM manually from psql. I find it convenient to use "\watch 0.01" to run VACUUM repeatedly. -- Peter Geoghegan
