RE: %lookup on a Data Structure Array

[Kurt Anderson <kurt.anderson@xxxxxxxxxxxxxx>]

I know we have programs that use that.  But it has to then load the entire table, when I only want two fields. 
Honestly I'm not concerned about the speed here.  

-Kurt

-----Original Message-----
From: rpg400-l-bounces+kurt.anderson=customcall.com@xxxxxxxxxxxx [mailto:rpg400-l-bounces+kurt.anderson=customcall.com@xxxxxxxxxxxx] On Behalf Of Carel Teijgeler
Sent: Thursday, November 10, 2011 3:28 PM
To: rpg400-l@xxxxxxxxxxxx
Subject: RE: %lookup on a Data Structure Array

Kurt,

As you already replied in another mail indicating you did, but have you looked at defining the file i n question as a Table file? (I know, an old technique).

In stead of typing an P for Primary or F for fully procedural you type in T. In the D-specs you have to link the file to the defined internal table.
IIRC, the columns in the internal table, should be adjacent fields from the file.

I just used this technique once, more than a decade ago, but the programme ran very fast. So my memory is very rusty on this.

Regards,
Carel Teijgeler

*********** REPLY SEPARATOR  ***********

On 10-11-2011 at 13:26 Kurt Anderson wrote:

> I'm aware of SETOBJACC, however I don't want this entire file in 
> memory,
only two fields.   Also, each of our clients has their own version of the
> file, so keeping it in memory doesn't seem like a viable option
regardless.
> I do need to retrieve a value, so I can't simply check for the 
> existence
of the record.
> I am aware of a potential performance hit of loading the array all at
once.  These are all batch jobs, and at most there would be 33k records
> (I'd define the array to be 50k to allow for growth), which is going to
load in seconds - so from a batch perspective, extra seconds once is ok.  
> However this discussion has given me the idea (or maybe someone 
> actually
mentioned this and I took it the wrong way, yet lead me to the same
> conclusion) that I could check the array.  If the customer isn't there,
then go to the file and get the value I need plus add the customer/value
> to the array.  So in the case of having 33k customers, maybe my job of
running 30 million records only uses 15k of those customers, then I've
> made the array smaller so the lookups would be quicker.
>
> This is all nice, however I think I need to enter a RFE for the RPG 
> team
to further enhance data structure array capability.
> In regard to User Indexes, I'm not sure where at the point of trade-off
occurs.  Like - when is it better to use a User Index than an array?  I'm
> sure there's presentations on that out there (and likely even on
conference CDs we have). 


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