Ivan Radovanovic <radovanovic@gmail.com> writes:
> Thanks Adrian, but question was how to decide which types are indexable
A little bit of research in the system-catalogs documentation will show
you how to find the types that can be accepted by some index opclass
(hint: "pg_opclass.opcintype::regtype").
As far as the other question goes, you could look for types that have a
pg_type.typmodin function -- though I'm not sure whether you want to
consider every possible usage of typmods as being a "precision".
regards, tom lane