Bug in plpython's Python Generators

Hi there,

I can't make Python Generators to work reliably.  According to the
documentation, this should work:

CREATE OR REPLACE FUNCTION foobar()
RETURNS SETOF text AS
$$
    for s in ('Hello', 'World'):
        plpy.execute('select 1')
        yield s
$$
LANGUAGE 'plpythonu';

I get this error when calling the function:

test=# select foobar();
ERROR:  error fetching next item from iterator
CONTEXT:  PL/Python function "foobar"


When I remove the dummy plpy.execute() call, it works:

CREATE OR REPLACE FUNCTION foobar()
RETURNS SETOF text AS
$$
    for s in ('Hello', 'World'):
        yield s
$$
LANGUAGE 'plpythonu';

test=# select foobar();
 foobar
--------
 Hello
 World
(2 rows)


Seems like calls to plpy.execute() conflict with generators.  This is
the case both on versions 8.4.4 and 9.0.1.

All the best,
-- 
Jean-Baptiste Quenot