The larger question to answer first is whether we want to implement > something that is deterministic... > > How about just dropping the whole concept of "hinting" and provide a way > for > someone to say "use this plan, or die trying." Maybe require it be used in > conjunction with named PREPAREd statements: >
You mean taking away the entire concept of query planning and cost estimation? Thats like replacing the optimizer with DBA decision and I am not at all comfortable with that idea. That are only my thoughts though. > > PREPARE s1 (USING /path/to/plan_def_on_server_or_something_similar) AS > SELECT ...; > > Aside from whole-plan specification I can definitely see where join/where > specification could be useful if it can overcome the current limitation of > not being able to calculate inter-table estimations. > Prepare plans use a generic plan for the execution. Replacing it with a totally user defined plan does not seem to be clean. The crux is that IMHO planner hints are a bad way of trying to circumvent the need for cross-column statistics. We should do cross-column statistics done and ignore planner hints completely. Regards, Atri -- Regards, Atri *l'apprenant*
