Re: Need a builtin way to run all tests faster manner

I wrote:
> I believe the core problem is that contrib/test_decoding's regresscheck
> and isolationcheck targets each want to use ./tmp_check as their
> --temp-instance. make has no reason to believe it shouldn't run those
> two sub-jobs in parallel, but when it does, we get two postmasters trying
> to share the same directory. This looks reasonably straightforward to
> solve, but I'm not entirely familiar with the code here, and am not
> sure what is the least ugly way to fix it.

Enlarging on that: if I cd into contrib/test_decoding and do
"make check -j4" or so, it reliably fails. With the attached patch,
it passes. This is a localized patch that only fixes things for
contrib/test_decoding; what I'm wondering is if it would be better to
establish a more widespread convention that $(pg_isolation_regress_check)
should use a different --temp-instance directory than $(pg_regress_check)
does.

regards, tom lane