Re: [PATCH] Support SK_SEARCHNULL / SK_SEARCHNOTNULL for heap-only scans

Hi,

On 2023-02-13 17:59:13 +0300, Aleksander Alekseev wrote:
> @@ -36,20 +36,36 @@ HeapKeyTest(HeapTuple tuple, TupleDesc tupdesc, int nkeys, ScanKey keys)
>          bool        isnull;
>          Datum        test;
>  
> -        if (cur_key->sk_flags & SK_ISNULL)
> -            return false;
> +        if (cur_key->sk_flags & (SK_SEARCHNULL | SK_SEARCHNOTNULL))
> +        {
> +            /* special case: looking for NULL / NOT NULL values */
> +            Assert(cur_key->sk_flags & SK_ISNULL);
>  
> -        atp = heap_getattr(tuple, cur_key->sk_attno, tupdesc, &isnull);
> +            atp = heap_getattr(tuple, cur_key->sk_attno, tupdesc, &isnull);
>  
> -        if (isnull)
> -            return false;
> +            if (isnull && (cur_key->sk_flags & SK_SEARCHNOTNULL))
> +                return false;
>  
> -        test = FunctionCall2Coll(&cur_key->sk_func,
> -                                 cur_key->sk_collation,
> -                                 atp, cur_key->sk_argument);
> +            if (!isnull && (cur_key->sk_flags & SK_SEARCHNULL))
> +                return false;

Shouldn't need to extract the column if we just want to know if it's NULL (see
heap_attisnull()). Afaics the value isn't accessed after this.

Greetings,

Andres Freund