Re: [GENERAL] Testing of MVCC

On Wed, 2005-08-10 at 16:41 -0400, Tom Lane wrote:
> Matt Miller <mattm(at)epx(dot)com> writes:
> > It seems to me that contrib/dblink could greatly simplify the design and
> > coding of multi-user regression tests.
>
> I doubt it would be very useful, since
> a script based on that still doesn't let you issue concurrent queries.

I think it would be useful to allow a test script to first create a set
of committed and uncommitted transactions, and to then issue some
queries on another connection to confirm that the other connection has a
proper view of the database at that point. This type of test is
serialized, but I think it would be a useful multi-user test. Also, the
output from such a test is probably pretty easy to fit into the
diff-based validation of "make check."

I realize that we also need to have tests that spawn several connections
and run scripts concurrently across those connections. I agree that
this type of test would probably not benefit fundamentally from
contrib/dblink. However, I was grasping a bit to see how the output
from such a concurrent test would be diff'ed with an expected output in
a meaningful way. So, to continue to progress on this problem, I
figured that a contrib/dblink dependency would at least allow me to
start coding something...

> > Is there objection to a portion
> > of src/test/regress depending on contrib/dblink?
>
> Yes.

Understood.