Re: Refactor function pg_get_multixact_stats (src/backend/utils/adt/multixactfuncs.c)

Hi Michael.

Em qua., 1 de jul. de 2026 às 00:18, Michael Paquier <michael(at)paquier(dot)xyz>
escreveu:

> On Tue, Jun 30, 2026 at 09:23:20AM -0300, Ranier Vilela wrote:
> > Move the GetMultiXactInfo() call and the resulting computations
> > into the branch where the values are actually consumed, narrowing
> > the scope of the related local variables to that branch. This
> > matches the usual pattern for privileged stats functions, which
> > skip the underlying work entirely for callers who can't see the
> > result, and avoids touching shared MultiXact state when there is no
> > caller around to observe it.
>
> That's indeed wasteful, so applied as it is my business.
>
Thanks for the commit.

>
> > While here, size the memset() that NULLs the output row off
> > sizeof(nulls) rather than *sizeof(bool) * tupdesc->natts*.
> > The two are equivalent today, since nulls is a fixed 4-element array
> > matching the function's declared return type, but relying the
> > memset() with *natts* is an unnecessary dependency.
> > If a column were ever added to the function's SQL definition without a
> > matching update to this array, the old code would silently write
> > past the end of nulls.
>
> But I left this one out. It's really impossible to miss.
>
I can send a separate patch.
What do you think?

best regards,
Ranier Vilela