Re: Suppressing occasional failures in copy2 regression test

Greg Stark <greg.stark@enterprisedb.com> writes:
> I'm not sure about that. It seems like race conditions with autovacuum  
> are a real potential bug that it would be nice to be testing for.

It's not a bug; it's a limitation of our testing framework that it sees
this as a failure.  Serious testing for autovac race conditions would
indeed be interesting, but you're never going to get anything meaningful
in that direction out of the current framework.

> Another solution would be adding an order by clause - effectively  
> trading coverage of unordered raw scans for coverage of the vacuum  
> races.

And destroying one of the main points of the copy2 test, which is that
those triggers are supposed to fire in a specific order.

> Or a third option would be adding alternate outputs for each ordering  
> we observe. I suspect there aren't that many for serial tests but I'm  
> less confident of that for the parallel tests.

There are several variants already observed, I believe, and I have
little confidence that there aren't more.  In any case, that's a kluge
not a solution, and it still degrades the ability of the test to cover
what it was designed to cover.
        regards, tom lane