"Marinos J. Yannikos" <[EMAIL PROTECTED]> writes: > it seems to me that the optimizer parameters (like random_page_cost > etc.) could easily be calculated and adjusted dynamically be the DB > backend based on the planner's cost estimates and actual run times for > different queries. Perhaps the developers could comment on that?
No, they are not that easy to determine. In particular I think the idea of automatically feeding back error measurements is hopeless, because you cannot tell which parameters are wrong. > I'm not sure how the parameters are used internally (apart from whatever > "EXPLAIN" shows), but if cpu_operator_cost is the same for all > operators, this should probably also be adjusted for individual > operators (I suppose that ">" is not as costly as "~*"). In theory perhaps, but in practice this is far down in the noise in most situations. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 8: explain analyze is your friend