As400 optimizer is driving me nuts again.
With DB2 UDB on Windows I basically indexed the proper fields,maintained statististics and reorganized if indicated.
Only in rare occasions the optimizer seemed to get lost.

Not so on AS400. I had to recompile a facttable and rebuild the indices according to plan. Prior to the recompiling, a 'heavy' query took about 60 seconds to complete.
Query performance is not down to 12-20 minutes, with explain plans that show a variety of access paths.

Does anyone know good solid documentation on the AS400 optimizer?
Every day I turn a little greyer