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That's true too! Clare ----- Original Message ----- From: <Jderham2@xxxxxx> To: <midrange-l@xxxxxxxxxxxx> Sent: Thursday, March 25, 2004 9:42 AM Subject: Re: Query optimizer tells me to build an access path that alreadyexists > In a message dated 3/25/2004 3:54:46 AM Eastern Standard Time, > Clare.Holtham@xxxxxxxxxxxxxx writes: > > That's one of the indexes you ALWAYS want to build. The Optimizer may well > > use it for statistics (data skew). Or it may want to use an index from index > > access method or whatever. > > Or do you mean you have already created the index? That can happen too. When > > the optimizer looks for an index, it may use different criteria or time out > > before it gets to the right one. These rules are different depending which > > version of the OS/400 you have. Sometimes it searches fifo, sometimes the > > other way, etc. > > If the file is really huge you could also try creating an EVA index. > > If you are on V5R2 there are now two different SQL Optimizers with different > > rules, and a new statistics gatherer. > > If you're in the US, I believe IBM do workshops on this subject.... > > > > cheers, > > > > Clare > > > > Clare Holtham > > Director, Small Blue Ltd - Archiving for BPCS > > Web: www.smallblue.co.uk > > IBM Certified AS/400 Systems Professional > Rumor has it that if you create the index with SQL rather then with DDS that > the SQL will like it more better. > Jack D. > > _______________________________________________ > This is the Midrange Systems Technical Discussion (MIDRANGE-L) mailing list > To post a message email: MIDRANGE-L@xxxxxxxxxxxx > To subscribe, unsubscribe, or change list options, > visit: http://lists.midrange.com/mailman/listinfo/midrange-l > or email: MIDRANGE-L-request@xxxxxxxxxxxx > Before posting, please take a moment to review the archives > at http://archive.midrange.com/midrange-l. >
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