Robert Haas <robertmh...@gmail.com> writes: > I'm a little mystified by exec_simple_check_node(). > ... > 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.
I think you might be right. The other way that I'm aware of that could cause interesting things to happen is if someone redefines a SQL function that had been inlined in the originally-compiled version of the expression. However, it should be the case that inline_function() will refuse to inline if the new definition contains anything "scary", so that the expression as seen by plpgsql is still simple; any non-simplicity will just be hidden under a function call. In fact, I suspect we could get rid of exec_simple_recheck_plan altogether. It could use a bit more study, but the empty-rtable check plus the other checks in exec_simple_check_plan (particularly, hasAggs, hasWindowFuncs, hasTargetSRFs, hasSubLinks) seem like they are enough to guarantee that what comes out of the planner will be "simple". If I recall things correctly, originally there were only the post-planning simplicity checks that are now embodied in exec_simple_recheck_plan/exec_simple_check_node. I think I added on the pre-planning checks in exec_simple_check_plan in order to try to save some planning cycles. Since the SRF checks were clearly still necessary at the time, I didn't think hard about whether any of the other post-planning checks could be got rid of. regards, tom lane -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers