Em ter., 26 de set. de 2023 às 07:34, Ashutosh Bapat < ashutosh.bapat....@gmail.com> escreveu:
> On Tue, Sep 26, 2023 at 3:32 PM David Rowley <dgrowle...@gmail.com> wrote: > > > > find_base_rel() could be made more robust for free by just casting the > > relid and simple_rel_array_size to uint32 while checking that relid < > > root->simple_rel_array_size. The 0th element should be NULL anyway, > > so "if (rel)" should let relid==0 calls through and allow that to > > ERROR still. I see that just changes a "jle" to "jnb" vs adding an > > additional jump for Ranier's version. [1] > > That's a good suggestion. > > I am fine with find_base_rel() as it is today as well. But > future-proofing it seems to be fine too. > > > > > It seems worth not making find_base_rel() more expensive than it is > > today as commonly we just reference root->simple_rel_array[n] directly > > anyway because it's cheaper. It would be nice if we didn't add further > > overhead to find_base_rel() as this would make the case for using > > PlannerInfo.simple_rel_array directly even stronger. > > I am curious, is the overhead in find_base_rel() impacting overall > performance? > It seems to me that it adds a LEA instruction. https://godbolt.org/z/b4jK3PErE Although it doesn't seem like much, I believe the solution (casting to unsigned) seems better. So +1. best regards, Ranier Vilela
