Re: tuplesort_putdatum() does not account for tuple memory

On Fri, 11 Sept 2026 at 08:36, Mario Karuza <mkaruza(dot)pg(at)icloud(dot)com> wrote:
> Memory allocated for copied pass-by-reference Datums was not accounted
> against work_mem because tuplesort_putdatum() passed a hardcoded tuplen
> of 0 to tuplesort_puttuple_common(). Function free_sort_tuple() adjusts
> the accounting by the amount actually allocated, so freeing such a
> tuple subtracts an amount that was never added.
>
> This was introduced in 6ed83d5fa55, which switched non-bounded sorts to
> bump contexts. That commit correctly changed the other tuplesort_put*()
> functions to compute the size, leaving only this one passing hardcoded
> 0.

I wondered if the extra strlen() call in datumGetSize() would result
in a slowdown, but looking deeper, it seems like that won't be hit due
to lack of sort support for cstring types.

I don't see any issues with the patch. I will process it on Monday, to
give time in case other people want to look.

David