numeric precision when raising one numeric to another.

[Scott Marlowe <smarlowe@xxxxxxxxxxxxxxxxx>]

It appears from checking the output of exponentiation of one numeric to
another, the output is actually in floating point.  Is this normal and /
or expected?

Now, given that

create table test2 (i1 numeric(20,0), i2 numeric(20,0));
insert into test values (123456789012345,123456789012345);
select i1*i2 from test2;
gives:
           ?column?
-------------------------------
 15241578753238669120562399025

it seems odd that

create table test (i1 numeric(20,0), i2 numeric(20,0));
insert into test values (2,55);
select i1^i2 from test;
gives:
      ?column?
---------------------
 3.6028797018964e+16

Now, I can get an exact answer if I'm willing to twiddle with breaking
the exponent down:

select (2^60)::numeric;

Gives:
       numeric
---------------------
 1152921504606850000

While, select (2^30)::numeric*(2^30)::numeric;

Gives:
      ?column?
---------------------
 1152921504606846976

So, numeric can hold the value, but it looks like the exponent math is
converting it to float.  

I'm not bothered too much by it, as I don't really work with numbers
that big.  I was mainly wondering if this is kosher is all.

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