Re: %lookup on a Data Structure Array

[jjcllhn@xxxxxxxxx]

What's the performance hit for processing the file using a VIEW that joins  
the base file with the lookup file versus the current process?

On , Kurt Anderson <kurt.anderson@xxxxxxxxxxxxxx> wrote:
> I'm trying to reduce some program I/O for program processing millions of  
> records. I've identified a file that I feel could be loaded into an array  
> instead of having the program chain out for every record. Usually this  
> file is between 100-1000 records. However one of our clients has 20,000  
> records in the file. So before making the change, I decided to do a  
> little reading on %lookup, to make sure I'd be using it correctly.

> http://www.ibmsystemsmag.com/ibmi/developer/rpg/iSeries-EXTRA--Look-Before-You--Lookup/



> It turns out that I had misunderstood how to trigger the binary search  
> with a %lookup. I thought sorting the array was enough, however to get  
> the binary search one needs to explicitly specify Ascend or Descend on  
> the array.



> So I went to add Ascend to a data structure array, and it won't let me:

> D ds_Cust DS Qualified Inz Dim( 50000 ) Ascend

> D Cust 3p 0

> D Cycle 1a

> Error: RNF3501E Keyword is not allowed for a data-structure definition;  
> keyword is ignored.



> I tried adding the Ascend keyword to the subfield that I use in the  
> lookup, but it doesn't like that either (I wasn't expecting this to work,  
> but at this point I'm grasping at straws).



> I suppose I could make these two fields their own arrays. Though I'm not  
> really a fan of that. I love using data structures to group like-data  
> together.



> Is there any way to get the new data structure array lookups to use a  
> binary search?



> Kurt Anderson

> Sr. Programmer/Analyst

> CustomCall Data Systems



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