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Message Posted: Mon, 01 Dec 2003 @ 10:27:14 GMT
you are right that R5 treats derived tables differently from R4. There is a setting that makes the R5 optimizer behave like R4. If you experience a lot of problems like the one you desribed you might want to look into that. Unforutnately I don't find the name of the setting in my notes, but you probably wouldn't want to make this change without working with your trusted NCR resource anyhow ;) [and they will know..]
2ndly I heard that V2r5 can take more spool in general, as the optimizer is more likely to favor redistriubtions over duplications compared to R4, so adjusting the spool might be needed anyhow.
Keep us posted - we use a lot of derived tables to force the execution plans as well, and I'd be interested in the experience you make along the upgrade. We plan to upgrade shortly too.
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