Re: check for null value before looking up the hash function - Mailing list pgsql-hackers

From Ranier Vilela
Subject Re: check for null value before looking up the hash function
Date
Msg-id CAEudQArxiozRn12BBgbe9RGm8=toNG3GyJO4uoddamcDK5x8jw@mail.gmail.com
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In response to Re: check for null value before looking up the hash function  (Ranier Vilela <ranier.vf@gmail.com>)
List pgsql-hackers
Em sáb., 21 de mai. de 2022 às 10:06, Ranier Vilela <ranier.vf@gmail.com> escreveu:
>Zhihong Yu <zyu(at)yugabyte(dot)com> writes:
>> I was looking at the code in hash_record()
>> of src/backend/utils/adt/rowtypes.c
>> It seems if nulls[i] is true, we don't need to look up the hash function.

>I don't think this is worth changing. It complicates the logic,
>rendering it unlike quite a few other functions written in the same
>style. In cases where the performance actually matters, the hash
>function is cached across multiple calls anyway. You might save
>something if you have many calls in a query and not one of them
>receives a non-null input, but how likely is that?

I disagree.
I think that is worth changing. The fact of complicating the logic
is irrelevant.
But maybe the v2 attached would be a little better.
Or v3.
 
regards,
Ranier Vilela
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