Re: More Hashing questions

If you do this I suggest supporting bigint as well.

On Tue, May 04, 2004 at 06:45:37PM -0400, Greg Stark wrote:
> 
> Regarding inter-data-type hash joins, would it make sense to make float
> datatypes to hash to the same value as integral data types for integral
> values?
> 
> Conveniently this would cover the existing special case of -0 and +0 hashing
> to the same value. Something like this?
> 
> Datum
> hashfloat4(PG_FUNCTION_ARGS)
> {
>     float4        key = PG_GETARG_FLOAT4(0);
> 
>         if (key == (int32)key)
>         PG_RETURN_UINT32(~(int32)key);
> 
>     return hash_any((unsigned char *) &key, sizeof(key));
> }
> 
> 
> Incidentally, why do all the floatfoo functions invert the value? It doesn't
> seem like that affects the quality of the hash at all.
> 
> 
> -- 
> greg
> 
> 
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Jim C. Nasby, Database Consultant                  jim@nasby.net
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