Re: argument type problem with plpgsql function

On Tue, 22 Nov 2005, Luca Pireddu wrote:

> I wrote a little function that has to work with big numbers
>
> CREATE OR REPLACE FUNCTION blast_evalue(seq_len bigint, db_size bigint,
> bit_score double precision)
>   RETURNS double precision AS $$
> BEGIN
>   RETURN 2^(bit_score) * db_size * seq_len;
> END;
> $$
> LANGUAGE 'plpgsql'
> IMMUTABLE
> RETURNS NULL ON NULL INPUT;
>
> but it doesn't work properly unless I cast the db_size parameter when I call
> the function:
>
> select blast_evalue(273, 8903836, -55.4546);
>  blast_evalue
> --------------
>    2430747228  <- wrong number.  This is 273 * 8903836
> (1 row)
>
> select blast_evalue(273, 8903836::bigint, -55.4546);
>     blast_evalue
> ---------------------
>  4.9231356421437e-08 <- that's correct
> (1 row)
>
> I don't understand why the cast is necessary.  Is there a way to make this
> work without it?

I got the same answer (the second) for both calls from my 8.0 and 8.1
setups, what version were you trying on?