On Tue, Nov 13, 2007 at 02:36:14PM -0500, Greg Smith wrote: > Sure, but in this case the reasoning seems sound enough.
Yes. But. . . > I see this as similar to the old optimizer hint argument, where there > certainly exist some edge cases where people know something the optimizer > doesn't which changes the optimal behavior. . . .the abuse of such hints in applications I have seen is so rampant as to make me doubt the utility of adding them anyway. It's true that by adding hints, you give a facility to a good, competent designer who has a really peculiar case that no general purpose system is likely to solve well. In practice, however, it also seems to mean that every slack-jawed fool with access to the manual thinks that he or she is going to "fix" the "broken" query plan by forcing index scans where they're useless (has a week yet gone by where someone doesn't post to -performance with that problem?). So I'm divided on whether actually providing the facility is a good idea, even though I can think of a handful of cases where I doubt even the smartest planner will get it right. (By analogy, pinning in memory, and I'm similarly divided.) A -- Andrew Sullivan Old sigs will return after re-constitution of blue smoke ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster
