Re: BitmapHeapScan streaming read user and prelim refactoring - Mailing list pgsql-hackers

Melanie Plageman <melanieplageman@gmail.com> writes:
> On Wed, Apr 24, 2024 at 4:46 PM Melanie Plageman
> <melanieplageman@gmail.com> wrote:
>> After thinking about it more, I suppose we can't add a test that
>> relies on the relation being all visible in the VM in a group in the
>> parallel schedule. I'm not sure this edge case is important enough to
>> merit its own group or an isolation test. What do you think?

> Andres rightly pointed out to me off-list that if I just used a temp
> table, the table would only be visible to the testing backend anyway.
> I've done that in the attached v2. Now the test is deterministic.

Hmm, is that actually true?  There's no more reason to think a tuple
in a temp table is old enough to be visible to all other sessions
than one in any other table.  It could be all right if we had a
special-case rule for setting all-visible in temp tables.  Which
indeed I thought we had, but I can't find any evidence of that in
vacuumlazy.c, nor did a trawl of the commit log turn up anything
promising.  Am I just looking in the wrong place?

            regards, tom lane