Re: Cost Based Optimizer

In article <25kfoiINN8t0@emory.mathcs.emory.edu>, estabroo@sea07s.navsea.navy.mil (Peter Estabrook) writes: |> I've come across an oddity with the Infromix cost base optimizer. It seems if |> you have a query that contains a matches on one column and an = on another it |> first uses the key on the column with the = and then it does a sequential |> search on the column with the matches. This is consistent with what I've seen. The cost-based optimizer, at least in SE, seems to consider "matches" a very poor choice even when there is an index on that field, and it will prefer almost any other criterion, even when the "matches" criterion is by far the best choice. In some of the cases I've run into, the "primitive" optimizer in 2.10.x made better choices than the new cost-based optimizer :-( Looking through the old articles I've got saved, I don't see any hints for dealing with this. If anyone has some good techniques for coercing the optimizer into doing something more sensible, I'd like to hear about it. -- Harry Bochner bochner@das.harvard.edu