Re: [Proposal] Expose internal MultiXact member count function for efficient monitoring

Hi,

On Fri, Oct 17, 2025 at 8:28 AM torikoshia <torikoshia(at)oss(dot)nttdata(dot)com> wrote:
>
> On 2025-09-15 14:47, Naga Appani wrote:
>
> > With these updates in v9, I believe the patch is now in good shape to
> > be marked RFC. I’ll go ahead and update the CommitFest entry.
>
> As shown in the commitfest app, v9 patch fails to build:
>
> multixactfuncs.c:129:28: error: call to undeclared function
> 'heap_form_tuple'; ISO C99 and later do not support implicit function
> declarations [-Wimplicit-function-declaration]
> 129 | return
> HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls));
> | ^
> multixactfuncs.c:129:28: note: did you mean 'brin_form_tuple'?
> ../../../../src/include/access/brin_tuple.h:96:19: note:
> 'brin_form_tuple' declared here
> 96 | extern BrinTuple *brin_form_tuple(BrinDesc *brdesc, BlockNumber
> blkno,
> | ^
> multixactfuncs.c:129:28: error: incompatible integer to pointer
> conversion passing 'int' to parameter of type 'const HeapTupleData *'
> (aka 'const struct HeapTupleData *') [-Wint-conversion]
> 129 | return
> HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls));
> |
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ../../../../src/include/funcapi.h:230:40: note: passing argument to
> parameter 'tuple' here
> 230 | HeapTupleGetDatum(const HeapTupleData *tuple)
> | ^
> 2 errors generated.
>
> Could you please update the patch to fix this?

Here’s the updated v10 patch, now including access/htup_details.h in
src/backend/utils/adt/multixactfuncs.c. I’m also interested in this
patch and plan to review it.

Best,
Xuneng