Re: random isolation test failures - Mailing list pgsql-hackers

From Alvaro Herrera
Subject Re: random isolation test failures
Date
Msg-id 1317149986-sup-664@alvh.no-ip.org
Whole thread Raw
In response to Re: random isolation test failures  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: random isolation test failures
List pgsql-hackers
Excerpts from Tom Lane's message of mar sep 27 01:11:39 -0300 2011:
>
> Alvaro Herrera <alvherre@commandprompt.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@commandprompt.com>
The PostgreSQL Company - Command Prompt, Inc.
PostgreSQL Replication, Consulting, Custom Development, 24x7 support

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