The main thing I'm wondering is how/if to handle backward compatibility with the existing NUMERIC and its DECIMAL alias, or whether adding new DECIMAL32, DECIMAL64, and DECIMAL128 types would be more appropriate. I'd love to just use the SQL standard types name DECIMAL if possible, and the standard would allow for it (see below), but backward compat would be a challenge, as would coming up with a sensible transparent promotion scheme from 32->64->128->numeric and ways to stop undesired promotion.
For what it's worth, DB2 9.5 and later call these types DECFLOAT(16) and DECFLOAT(34), and they are distinct from DECIMAL/NUMERIC.
