Quirk

Hm, in psql if I set FETCH_COUNT to a nonzero value I suddenly find I'm unable
to use SELECT ... FOR UPDATE.

I suspect this is unnecessary, that the only reason cursors can't hold locks
is because we don't support the kind of read-write operations that clients may
expect to be able to issue against read-write cursors? But if we're using
cursors to work around the libpq interface limitations then perhaps this
restriction shouldn't apply?

postgres=# select * from test for update;
ERROR:  DECLARE CURSOR ... FOR UPDATE/SHARE is not supported
DETAIL:  Cursors must be READ ONLY.

--  Gregory Stark EnterpriseDB          http://www.enterprisedb.com