Re: xid_wraparound tests intermittent failure.

On Mon, Jul 22, 2024 at 12:53 PM Andrew Dunstan <andrew@dunslane.net> wrote:

On 2024-07-22 Mo 12:46 PM, Tom Lane wrote:

Masahiko Sawada <sawada.mshk@gmail.com> writes:

Looking at dodo's failures, it seems that while it passes
module-xid_wraparound-check, all failures happened only during
testmodules-install-check-C. Can we check the server logs written
during xid_wraparound test in testmodules-install-check-C?

Oooh, that is indeed an interesting observation.  There are enough
examples now that it's hard to dismiss it as chance, but why would
the two runs be different?


It's not deterministic.

I tested the theory that it was some other concurrent tests causing the issue, but that didn't wash. Here's what I did:
    for f in `seq 1 100`      do echo iteration = $f      meson test --suite xid_wraparound || break    done

It took until iteration 6 to get an error. I don't think my Ubuntu instance is especially slow. e.g. "meson compile" normally takes a handful of seconds. Maybe concurrent tests make it more likely, but they can't be the only cause.

Could you provide server logs in both OK and NG tests? I want to see
if there's a difference in the rate at which tables are vacuumed.

See <https://bitbucket.org/adunstan/rotfang-fdw/downloads/xid-wraparound-result.tar.bz2>

The failure logs are from a run where both tests 1 and 2 failed.

cheers

andrew

--
Andrew Dunstan
EDB: https://www.enterprisedb.com