Re: VARIANT / ANYTYPE datatype

To follow-up my earlier comments ...

I suspect for practical purposes we may want to limit the scope of some type 
features.

For example, the greatest benefits for "open union" / "mixin" types is with 
routines/operators, not so much with tables.

So, Pg could choose to support open unions but only for routines, where the 
declared types of table columns must still be other types.  Then you don't have 
to worry about searching your data for where one might be used, but only search 
your system catalog for routines/operators that use it.

But closed unions should be supported in tables too.

-- Darren Duncan