Re: Extract numeric filed in JSONB more effectively

Hi

čt 3. 8. 2023 v 2:51 odesílatel Andy Fan <zhihui.fan1213@gmail.com> napsal:

> Hi Jian:
>
>
>> return PointerGetDatum(v->val.numeric);
>> should be something like
>> PG_RETURN_NUMERIC(v->val.numeric);
>> ?
>>
>
> Thanks for this reminder, a new patch is attached.  and commitfest
> entry is added as well[1]. For recording purposes,  I compared the
> new operator with all the existing operators.
>
> select 1 from tb where (a->'a')::numeric = 2;   30.56ms
> select 1 from tb where (a->>'a')::numeric = 2; 29.43ms
> select 1 from tb where (a@->'a') = 2;              14.80ms
>
> [1] https://commitfest.postgresql.org/44/4476/
>
>
I don't like this solution because it is bloating  operators and it is not
extra readable. For completeness you should implement cast for date, int,
boolean too. Next, the same problem is with XML or hstore type (probably
with any types that are containers).

It is strange so only casting is 2x slower. I don't like the idea so using
a special operator is 2x faster than common syntax for casting. It is a
signal, so there is a space for optimization. Black magic with special
operators is not user friendly for relatively common problems.

Maybe we can introduce some *internal operator* "extract to type", and in
rewrite stage we can the pattern (x->'field')::type transform to OP(x,
'field', typid)

Regards

Pavel


-- 
> Best Regards
> Andy Fan
>