Re: Yet another fast GiST build

On 30/10/2020 20:20, Andrey Borodin wrote:
>> 27 окт. 2020 г., в 16:43, Heikki Linnakangas <hlinnaka(at)iki(dot)fi> написал(а):
>>> static bool
>>> gbt_inet_abbrev_abort(int memtupcount, SortSupport ssup)
>>> {
>>> #if SIZEOF_DATUM == 8
>>> return false;
>>> #else
>>> return true;
>>> #endif
>>> }
>>
>> Better to not set the 'abbrev_converter' function in the first place. Or would it be better to cast the float8 to float4 if SIZEOF_DATUM == 4?
> Ok, now for 4 bytes Datum we do return (Datum) Float4GetDatum((float) z);

A few quick comments:

* Currently with float8, you immediately abort abbreviation if
SIZEOF_DATUM == 4. Like in the 'inet' above, you could convert the
float8 to float4 instead.

* Some of the ALTER OPERATOR FAMILY commands in btree_gist--1.6--1.7.sql
are copy-pasted wrong. Here's one example:

ALTER OPERATOR FAMILY gist_timestamptz_ops USING gist ADD
FUNCTION 11 (text, text) gbt_text_sortsupport;

* It's easy to confuse the new comparison functions with the existing
comparisons used by the picksplit functions. Some comments and/or naming
changes would be good to clarify how they're different.

* It would be straightforward to have abbreviated functions for macaddr
and macaddr8 too.

> How do you think, should this patch and patch with pageinspect GiST functions be registered on commitfest?

Yeah, that'd be good.

- Heikki