"Jonah H. Harris" <jonah.harris@gmail.com> writes:
> On 10/26/06, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> This makes some really quite unacceptable assumptions about
>> the meaning and encoding of typmod ...
>
> True, so VARCHAR seems like the only one? That's the only one I've
> really encountered in the field on a fairly regular basis.
I think what you want is to add a new method entry in pg_type to allow a type
to declare a method to tell you whether a change is work-free or not. Then any
type, even user-defined types, can allow some changes to be work-free and some
not without exposing any implementation details outside the type.
--
Gregory Stark
EnterpriseDB http://www.enterprisedb.com