Re: Yet another fast GiST build

On 09/09/2020 19:50, Andrey M. Borodin wrote:
>> 9 сент. 2020 г., в 20:39, Heikki Linnakangas <hlinnaka@iki.fi> написал(а):
>>
>> On 09/09/2020 15:20, Darafei "Komяpa" Praliaskouski wrote:
>>> On Wed, Sep 9, 2020 at 3:09 PM Heikki Linnakangas <hlinnaka@iki.fi> wrote:
>>>> Come to think of it, the point z-order comparator could benefit a lot
>>>> from key abbreviation, too. You could do the point -> zorder conversion
>>>> in the abbreviation routine.
>>> That's how it works in PostGIS, only that we moved to more
>>> effecient Hilbert curve:
>>> https://github.com/postgis/postgis/blob/54399b9f6b0f02e8db9444f9f042b8d4ca6d4fa4/postgis/lwgeom_btree.c#L171
>>
>> Thanks, that's interesting.
>>
>> I implemented the abbreviated keys for the point opclass, too, and noticed that the patch as it was never used it. I
reworkedthe patch so that tuplesort_begin_index_gist() is responsible for looking up the sortsupport function, like
tuplesort_begin_index_btree()does, and uses abbreviation when possible.
 
> Wow, abbreviated sort made gist for points construction even 1.5x faster!
> btw there is small typo in arg names in gist_bbox_zorder_cmp_abbrev(); z1,z2 -> a,b

One more patch version attached. I fixed some memory leaks, and fixed 
the abbreviation on 32-bit systems, and a bunch of small comment changes 
and such.

- Heikki