Re: Fix RETURNING side effects for FOR PORTION OF leftover rows

> On Jul 20, 2026, at 16:56, Dean Rasheed <dean(dot)a(dot)rasheed(at)gmail(dot)com> wrote:
>
> On Thu, 16 Jul 2026 at 07:20, Chao Li <li(dot)evan(dot)chao(at)gmail(dot)com> wrote:
>
>> To fix the problem, since leftover rows are inserted by calling ExecInsert(), and ExecInsert() is a local static function, I think a simple and safe solution is to add a new parameter to ExecInsert() to indicate whether to process RETURNING for this insert. Then UPDATE/DELETE FOR PORTION OF can bypass RETURNING processing for leftover rows.
>
> I don't particularly like adding another argument to ExecInsert(). I
> think it can work out from its existing arguments whether it's part of
> a FOR PORTION OF query (by looking at mtstate).
>

Okay. We cannot simply check node->forPortionOf to bypass RETURNING processing, because an FPO update on a partitioned table may move a row to a different partition. In that case, ExecInsert() is also called to insert the row into the new partition.

However, in that case, mtstate->operation is still CMD_UPDATE, while for leftover rows, mtstate->operation is temporarily changed to CMD_INSERT. So we can check both node->forPortionOf and mtstate->operation.

PFA v2 with the new implementation. I tried to run check-world and it passed.

Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/