Re: Possible problem in Custom Scan API

Dmitry Ivanov <d(dot)ivanov(at)postgrespro(dot)ru> writes:
>> Reading between the lines, I think the problem may be that you're not
>> being careful about how you set up custom_scan_tlist. But since the
>> core code has zero involvement in that decision, it's hard to see why
>> it would be a core code bug.

> I'm sorry, but you didn't understand. It's *the core code* that builds the
> targetlist, and sometimes it may decide to provide a physical targetlist,
> not the one that's *really needed*.

Uh, no, construction of a custom plan node is entirely driven by the
PlanCustomPath method as far as I can see. You're free to ignore what
create_scan_plan did and insert your own tlist. In particular, if what
your custom path actually is is a rescan of something like an
IndexOnlyScan, why don't you just copy the IOS's result tlist?

regards, tom lane