Re: random isolation test failures

Excerpts from Tom Lane's message of mar sep 27 01:11:39 -0300 2011:
>
> Alvaro Herrera <alvherre(at)commandprompt(dot)com> writes:
> > I just tweaked isolationtester so that it collects the error messages
> > and displays them all together at the end of the test. After seeing it
> > run, I didn't like it -- I think I prefer something more local, so that
> > in the only case where we call try_complete_step twice in the loop, we
> > report any errors in either. AFAICS this would make both expected cases
> > behave identically in test output.
>
> Hmm, is that really an appropriate fix? I'm worried that it might mask
> event-ordering differences that actually are significant.

In the attached, it only affects the case where there is one blocking
command and another command that unblocks it; this is only exercised by
the much-beaten fk-deadlock cases. If either of the steps fails with a
deadlock error, it is reported identically, i.e. the error message is
emitted as

"error in s1u1 s2u1: ERROR: deadlock detected"

So the deadlock could have been detected in either s1u1 or s2u1; we
don't really care.

The way error messages are reported in all the other cases is not
changed, and these do not have a prefix; so if anything were to behave
differently, we would find out because a spurious prefix would appear.

--
Álvaro Herrera <alvherre(at)commandprompt(dot)com>
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