Re: Yet another fast GiST build - Mailing list pgsql-hackers

On 08/03/2021 19:06, Andrey Borodin wrote:
> There were numerous GiST-build-related patches in this thread. Yet uncommitted is a patch with sortsupport routines
forbtree_gist contrib module.
 
> Here's its version which needs review.

Reviewing this now again. One thing caught my eye:

> +static int
> +gbt_bit_sort_build_cmp(Datum a, Datum b, SortSupport ssup)
> +{
> +    return DatumGetInt32(DirectFunctionCall2(byteacmp,
> +                                             PointerGetDatum(a),
> +                                             PointerGetDatum(b)));
> +}

That doesn't quite match the sort order used by the comparison 
functions, gbt_bitlt and such. The comparison functions compare the bits 
first, and use the length as a tie-breaker. Using byteacmp() will 
compare the "bit length" first. However, gbt_bitcmp() also uses 
byteacmp(), so I'm a bit confused. So, huh?

- Heikki