On 2020-09-06 05:04, Michael Paquier wrote:
I would allow 0. It's not
very useful, but it's not harmful and could be applicable in testing.
Hmm, OK. For pg_test_fsync, 0 means infinity, and for pg_test_timing
that means stopping immediately (we currently don't allow that). How
does this apply to testing? For pg_test_fsync, using 0 would mean to
just remain stuck in the first fsync() pattern, while for
pg_test_fsync this means doing no test loops at all, generating a
useless log once done. Or do you mean to change the logic of
pg_test_fsync so as --secs-per-test=0 means doing one single write?
That's something I thought about for this thread, but I am not sure
that the extra regression test gain is worth more complexity in this
code.
I think in general doing something 0 times should be allowed if possible.
However, I see that in the case of pg_test_fsync you end up in alarm(0),
which does something different, so it's okay in that case to disallow it.
I notice that the error checking you introduce is different from the
checks for pgbench -t and -T (the latter having no errno checks). I'm
not sure which is correct, but it's perhaps worth making them the same.
(pgbench -t 0, which is also currently not allowed, is a good example of
why this could be useful, because that would allow checking whether the
script etc. can be loaded without running an actual test.)
--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
