Re: Vacuum ERRORs out considering freezing dead tuples from before OldestXmin

Melanie Plageman <melanieplageman@gmail.com> writes:
> We've only run tests with this commit on some of the back branches for
> some of these animals. Of those, I don't see any failures so far. So,
> it seems the test instability is just related to trying to get
> multiple passes of index vacuuming reliably with TIDStore.

> AFAICT, all the 32bit machine failures are timeouts waiting for the
> standby to catch up (mamba, gull, merswine). Unfortunately, the
> failures on copperhead (a 64 bit machine) are because we don't
> actually succeed in triggering a second vacuum pass. This would not be
> fixed by a longer timeout.

Ouch.  This seems to me to raise the importance of getting a better
way to test multiple-index-vacuum-passes.  Peter argued upthread
that we don't need a better way, but I don't see how that argument
holds water if copperhead was not reaching it despite being 64-bit.
(Did you figure out exactly why it doesn't reach the code?)

> Because of this, I'm inclined to revert the test on 17 and master to
> avoid distracting folks committing other work and seeing those animals
> go red.

Agreed as a short-term measure.

            regards, tom lane