Probably QueryCompletion struct fits this purpose best from the existing parameters. Attached draft patch implements returning oid of newly created relation as part of QueryCompletion. Thoughts?
I agree, returning the oid of the newly created relation is the best way to solve the problem. (Excuse me, I won't have access to a laptop for the next week - and won't be able to look at the source code).
-- With best regards, Dmitry Koval Postgres Professional: http://postgrespro.com