I'm a little mystified by exec_simple_check_node(). The regression tests seem not to exercise it. It can only be reached when exec_simple_recheck_plan() finds no other reason to reject the plan, and the only case it seems to reject is the one where there's a set-returning function buried in there someplace. But then it seems like hasTargetSRFs would have been true and we would have given up before making a plan in the first place. Of course, that only protects us when originally forming the plan; they don't account for later changes -- and the code comments claim that an expression which was originally simple can become non-simple:
* It is possible though unlikely for a simple expression to become non-simple * (consider for example redefining a trivial view). But I can't quite figure that one out. If we're selecting from a trivial view, then the range table won't be empty and the expression won't be simple in the first place. The check for a non-empty range table didn't exist when this comment was originally added (95f6d2d20921b7c2dbec29bf2706fd9448208aa6, 2007); it was added in a subsequent redesign (e6faf910d75027bdce7cd0f2033db4e912592bcc; 2011). Did that, possibly, remove the last way in which a simple expression could be could become non-simple? If so, between that and the new hasTargetSRFs test, it might now be impossible for exec_simple_check_node() to fail. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers