Re: Timeout control within tests

Noah Misch <noah@leadboat.com> writes:
> On Thu, Feb 17, 2022 at 09:48:25PM -0800, Andres Freund wrote:
>> Meson's test runner has the concept of a "timeout multiplier" for ways of
>> running tests. Meson's stuff is about entire tests (i.e. one tap test), so
>> doesn't apply here, but I wonder if we shouldn't do something similar?

> Hmmm.  It is good if the user can express an intent that continues to make
> sense if we change the default timeout.  For the buildfarm use case, a
> multiplier is moderately better on that axis (PG_TEST_TIMEOUT_MULTIPLIER=100
> beats PG_TEST_TIMEOUT_DEFAULT=18000).  For the hacker use case, an absolute
> value is substantially better on that axis (PG_TEST_TIMEOUT_DEFAULT=3 beats
> PG_TEST_TIMEOUT_MULTIPLIER=.016666).

FWIW, I'm fairly sure that PGISOLATIONTIMEOUT=300 was selected after
finding that smaller values didn't work reliably in the buildfarm.
Now maybe 741d7f1 fixed that, but I wouldn't count on it.  So while I
approve of the idea to remove PGISOLATIONTIMEOUT in favor of using this
centralized setting, I think that we might need to have a multiplier
there, or else we'll end up with PG_TEST_TIMEOUT_DEFAULT set to 300
across the board.  Perhaps the latter is fine, but a multiplier seems a
bit more flexible.

On the other hand, I also support your point that an absolute setting
is easier to think about / adjust for special uses.  So maybe we should
just KISS and use a single absolute setting until we find a hard reason
why that doesn't work well.

			regards, tom lane