Re: SKIP LOCKED DATA (work in progress)

On 29 July 2014 02:35, Alvaro Herrera <alvherre@2ndquadrant.com> wrote:
> David Rowley wrote:
>
>> I've also been looking at the isolation tests and I see that you've added a
>> series of tests for NOWAIT. I was wondering why you did that as that's
>> really existing code, probably if you thought the tests were a bit thin
>> around NOWAIT then maybe that should be a separate patch?
>
> The isolation tester is new so we don't have nearly enough tests for it.
> Adding more meaningful tests is good even if they're unrelated to the
> patch at hand.

Here are my isolation tests for NOWAIT as a separate patch,
independent of SKIP LOCKED.  They cover the tuple lock, regular row
lock and multixact row lock cases.  I guess this might be called white
box testing, since it usese knowledge of how to construct schedules
that hit the three interesting code paths that trigger the error, even
though you can't see from the output why the error was raised in each
case without extra instrumentation (though it did cross my mind that
it could be interesting at the very least for testing if the error
message were different in each case).  If there are no objections I
will add this to the next commitfest.

Best regards
Thomas Munro