got it, thanks for the explanation.
On Wed, Apr 27, 2022 at 11:34 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> Junwang Zhao <zhjwpku@gmail.com> writes:
> > In function ItemPointerEquals, the ItemPointerGetBlockNumber
> > already checked the ItemPointer if valid, there is no need
> > to check it again in ItemPointerGetOffset, so use
> > ItemPointerGetOffsetNumberNoCheck instead.
>
> I do not think this change is worth making. The point of
> ItemPointerGetOffsetNumberNoCheck is not to save some cycles,
> it's to be able to fetch the offset field in cases where it might
> validly be zero. The assertion will be compiled out anyway in
> production builds --- and even in assert-enabled builds, I'd kind
> of expect the compiler to optimize away the duplicated tests.
>
> regards, tom lane
--
Regards
Junwang Zhao