Re: SKIP LOCKED DATA (work in progress)

On 28 August 2014 00:25, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> wrote:
> Thomas Munro wrote:
>> I haven't yet figured out how to get get into a situation where
>> heap_lock_updated_tuple_rec waits.
>
> Well, as I think I said in the first post I mentioned this, maybe there
> is no such situation. In any case, like the EvalPlanQualFetch issue, we
> can fix it later if we find it.

I finally came up with a NOWAIT spec that reaches
heap_lock_updated_rec and then blocks. I can't explain why exactly...
but please see attached. The fix seems fairly straightforward. Do
you think I should submit an independent patch to fix this case (well
there are really two cases, since there is a separate multixact path)
for the existing NOWAIT support and then tackle the SKIP LOCKED
equivalent separately?

Best regards,
Thomas Munro