Re: Bug in GiST paring heap comparator

From: Alexander Korotkov <a(dot)korotkov(at)postgrespro(dot)ru>
To: Nikita Glukhov <n(dot)gluhov(at)postgrespro(dot)ru>
Cc: pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>, Heikki Linnakangas <hlinnaka(at)iki(dot)fi>
Subject: Re: Bug in GiST paring heap comparator
Date: 2019-09-16 19:30:38
Message-ID: CAPpHfdsnNdryJ765=oqw16Nv4fKdHEJ+T5Tm07asOL6a4s3W9g@mail.gmail.com
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On Mon, Sep 16, 2019 at 3:47 PM Nikita Glukhov <n(dot)gluhov(at)postgrespro(dot)ru> wrote:
> On 13.09.2019 20:17, Alexander Korotkov wrote:
>
> 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.
>
> Propagation of IndexOrderByDistance in SP-GiST was extracted into a separate
> patch #2.

First patch is minor editing from me and commit message is attached.
I'm going to push it if no objections.

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

Attachment Content-Type Size
0001-Fix-GiST-and-SP-GiST-ordering-by-distance-for-NULLs-v4.patch application/octet-stream 23.3 KB

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