Re: Vacuum ERRORs out considering freezing dead tuples from before OldestXmin - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Vacuum ERRORs out considering freezing dead tuples from before OldestXmin
Date
Msg-id 729493.1721595882@sss.pgh.pa.us
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In response to Re: Vacuum ERRORs out considering freezing dead tuples from before OldestXmin  (Peter Geoghegan <pg@bowt.ie>)
Responses Re: Vacuum ERRORs out considering freezing dead tuples from before OldestXmin
Re: Vacuum ERRORs out considering freezing dead tuples from before OldestXmin
List pgsql-hackers
Peter Geoghegan <pg@bowt.ie> writes:
> On Sun, Jul 21, 2024 at 12:51 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> I do not think the answer to this is to nag the respective animal
>> owners to raise PG_TEST_TIMEOUT_DEFAULT.  IMV this test is simply
>> not worth the cycles it takes, at least not for these machines.

> Can't we just move it to PG_TEST_EXTRA? Alongside the existing
> "xid_wraparound" test?

Perhaps.  xid_wraparound seems entirely too slow for what it's
testing as well, if you ask me, and there's a concurrent thread
about that test causing problems too.

> There will always be a small number of extremely slow buildfarm
> animals. Optimizing for things like Raspberry pi animals with SD cards
> just doesn't seem like a good use of developer time. I really care
> about keeping the tests fast, but only on platforms that hackers
> actually use for their development work.

I find this argument completely disingenuous.  If a test is slow
enough to cause timeout failures on slower machines, then it's also
eating a disproportionate number of cycles in every other check-world
run --- many of which have humans waiting for them to finish.  Caring
about the runtime of test cases is good for future-you not just
obsolete buildfarm animals.

I note also that the PG_TEST_EXTRA approach has caused xid_wraparound
to get next-to-zero buildfarm coverage.  If that test is actually
capable of revealing problems, we're unlikely to find out under the
status quo.

            regards, tom lane



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