On Mon, 2007-01-15 at 13:54 -0500, Neil Conway wrote: > On Mon, 2007-01-15 at 10:51 -0800, Richard Troy wrote: > > I therefore propose that the engine evaluate - > > benchmark, if you will - all functions as they are ingested, or > > vacuum-like at some later date (when valid data for testing may exist), > > and assign a cost relative to what it already knows - the built-ins, for > > example. > > That seems pretty unworkable. It is unsafe, for one: evaluating a > function may have side effects (inside or outside the database), so the
Would any form of cost estimate have meaning if the function has side effects? If it's a volatile function, doesn't that mean that the planner can't avoid or favor executing it? Regards, Jeff Davis ---------------------------(end of broadcast)--------------------------- TIP 7: You can help support the PostgreSQL project by donating at http://www.postgresql.org/about/donate