Re: Structure of logical file for query

[Charles Wilt <charles.wilt@xxxxxxxxx>]

Tomasz,

The answer usually is it depends. :)

You can find some good information here:
Indexing and Statistics Strategies for DB2 UDB for iSeries
http://www-03.ibm.com/servers/enable/site/bi/strategy/strategy.pdf

But in the end, you'll want to run your query through iSeries
Navigator's Visual Explain and see what it tells you.

Have Fun!
Charles

2010/1/4 Tomasz Skorża <t.skorza@xxxxxxxxxxx>:
> Hi and happy New Year for everybody :-)
>
> I would like to ask you how you create keyed fields for logical file for
> get the fastest "access".
>
> I have such query
>
> Select F1, F2, F3
>  From File1
> Where
> F4, F5, F6
> Group By F1, F2, F3
> Order by F1, F2, F3
>
> I looking in many web pages but everywhere description of creating LF is
> general - "Logicals are important to improve performance"
>
> But what should be an order of keyed fields?
>
> What if query change to:
>
> Select F1, F2, F3
>  From File1
> Where
> F4, F5, F6
> Group By F7, F8, F9
> Order by F9, F8, F7
>
> Which statement are most important? Probably "WHERE" ... but order
> should be F4/F5/F6 or other (F6/F5/F4)?
>
> Do you remember a web pages where it is described exactly?
>
> --
> Pozdrawiam
>
> ---------------------------------------------------------
> Tomasz Skorża
>
>
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