Re: %lookup on a Data Structure Array

While not a direct answer to your exact question, I would strongly consider using USRIDX instead of a lookup array. It's more code (but only once, if done correctly), and will give you the efficiency you seek. However, I have never seen a performance comparison between %LOOKUP and User Index lookups.

My direct answer is that I'm not aware of any means of doing what you ask.
++
Dennis
++


Sent from my Galaxy tablet phone. Please excuse my brevity.
For any grammatic/spelling errors, there is no excuse.
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"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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