Re: Query optimizer tells me to build an access path that already exists

[Jderham2@xxxxxx]

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.