On Tue, Oct 31, 2023 at 1:36 PM Andrei Lepikhov <a.lepik...@postgrespro.ru> wrote:
> On 30/10/2023 14:55, Richard Guo wrote: > > > > On Thu, Oct 26, 2023 at 12:07 PM Andrei Lepikhov > > <a.lepik...@postgrespro.ru <mailto:a.lepik...@postgrespro.ru>> wrote: > > > > Do you've thought about the case, fixed with the commit 1db5667? As I > > see, that bugfix still isn't covered by regression tests. Could your > > approach of a PARAM_EXEC slot reusing break that case? > > > > > > Hm, I don't think so. The issue fixed by commit 1db5667 was caused by > > sharing PARAM_EXEC slots between different levels of NestLoop. AFAICS > > it's safe to share PARAM_EXEC slots within the same level of NestLoop. > > > > The change here is about sharing PARAM_EXEC slots between subquery's > > subplan_params and outer-relation variables, which happens within the > > same level of NestLoop. > > ... > > Did you notice a case that the change here breaks? > > > > Hi Tom, could you share your insights on this issue and the proposed > > fix? > > I think your patch works correctly so far. I mentioned the commit > 1db5667 because, as I see, the origin of the problem was parallel > workers. I have thought about pushing Memoize down to a parallel worker > and couldn't imagine whether such a solution would be correct. > Sorry if I disturbed you in vain. Thanks for mentioning commit 1db5667, which brings my attention to more aspects about the PARAM_EXEC mechanism. I don't think the discussion is in vain. It helps a lot. Thanks for looking into this patch. Thanks Richard
