On Sat, 20 Jul 2024 at 17:26, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> The existing code/comments (dating AFAICS to Dean's cab5dc5da)
> already point out that rewriteTargetListIU can add targetlist items,
> but we missed the fact that it can delete them too. So it seems like
> what we need to do is union the original set of target columns with
> what's listed in the targetlist, as attached.
>
Ah yes, that makes sense and the fix looks good. Thanks for taking care of that.
I had always thought that rewriteTargetListIU() only ever added or
merged items, somehow overlooking the fact that it could also delete
them. In my defence, it's very easy to get that impression just by
reading the function's comments. I think it's worth updating those
comments to mention that. Something like the attached, perhaps.
Regards,
Dean