Re: Allow round() function to accept float and double precision - Mailing list pgsql-hackers

David Rowley <dgrowleyml@gmail.com> writes:
> We do have some weirdness in some existing overloaded functions.
> pg_size_pretty() is an example.

> If you run: SELECT pg_size_pretty(1000); you get:
> ERROR:  function pg_size_pretty(integer) is not unique

Yeah, you have to be careful about that when proposing to overload
a function name.

> That occurs because we don't know if we should promote the INT into a
> BIGINT or into a NUMERIC. We have a pg_size_pretty() function for each
> of those.  I don't think the same polymorphic type resolution problem
> exists for REAL, FLOAT8 and NUMERIC.

I would counsel against bothering with a REAL version.  FLOAT8 will
cover that case just fine.

> I'm unsure what the repercussions of the fact that REAL and FLOAT8 are
> not represented as decimals.

The main thing is that I think the output will still have to be
NUMERIC, or you're going to get complaints about "inaccurate"
results.  Before we got around to inventing infinities for NUMERIC,
that choice would have been problematic, but now I think it's OK.

            regards, tom lane