Re: Bug in GiST paring heap comparator

On Fri, Sep 13, 2019 at 5:23 PM Nikita Glukhov <n(dot)gluhov(at)postgrespro(dot)ru> wrote:
> I have moved handling of NULL ordering keys from opclasses to the common
> SP-GiST code, but really I don't like how it is implemented now. Maybe it's
> worth to move handling of NULL order-by keys to the even more higher
> level so,
> that AM don't have to worry about NULLs?

Yes, optimizer could remove away "col op NULL" clauses from ORDER BY
if op is strict operator. And then such clauses wouldn't be passed to
AM. But I see this as future improvement. For backpatching we should
solve this at AM side.

> Also I leaved usages of IndexOrderByDistance in opclasses. I think, that
> may
> help to minimize opclass changes in the future.

Could you please extract this as a separate patch. We can consider
this for master, but we shouldn't backpatch this.

------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company