BUG #8199: row datatypes are not hashable

The following bug has been logged on the website:

Bug reference: 8199
Logged by: Rafal Rzepecki
Email address: divided(dot)mind(at)gmail(dot)com
PostgreSQL version: 9.2.4
Operating system: Ubuntu 13.04
Description:

Row datatypes are currently not hashable, which makes it slower to use them
in a UNIQUEd query and impossible to use them in a recursive query (unless
using UNION ALL):

divide=# create type the_row as (mfg text, id text);
CREATE TYPE
divide=# with recursive rec(w, i) as (

select '(pow,xyzzy)'::the_row, 3
union
select w, i-1 from rec where i > 0
) select * from rec;
ERROR: could not implement recursive UNION
DETAIL: All column datatypes must be hashable.