Re: How can I Improve this procedure... -- RPG400-L

How can I improve this procedure for performance? I am a little worried
about how the ReasonDS is declared.
Basically I need an Array of the Datastructure that the procedure can
return. I also need to be able to look up this array with @RsnCode as the
key.

The best way to improve performance is to pass the data structure as aparameter instead of as a return value. The return value is much lessefficient, and I personally would never use it for anything larger than 30bytes (or so) if performance is a concern.

* Array of Data structures to hold reason code details
D  ReasonDS       DS          5400
D   @RsnCode                     2A   Dim(200)
D   @Charge                      9  2 Dim(200)
D   @Weight                      9  0 Dim(200)
D   @Units                       7  0 Dim(200)

This isn't an array of data structures. It's a data structure thatcontains 4 arrays, each array is independent of the others. I also don'tunderstand why you've hardcoded the data structure to be 5400 bytes longwhen it actually only needs 3200 bytes of memory. I know that 2200 bytesisn't a big deal, but why waste it if it brings you no benefit at all?


You probably meant to do this:

     D                 DS
     D ReasonDS                            dim(200)
     D  @RsnCode                      2A   overlay(ReasonDS:1)
     D  @Charge                       9P 2 overlay(ReasonDS:*NEXT)
     D  @Weight                       9P 0 overlay(ReasonDS:*NEXT)
     D  @Units                        7P 0 overlay(ReasonDS:*NEXT)

In this case, "ReasonDS" is an array of 16A DIM(200). The other fieldsoverlay positions in that array, so @RsnCode is an array that alwaysoverlays positions 1-2 of ReasonDS. @Charge is an array that overlayspositions 3-7 of ReasonDS, etc.


Alternately, you could code it as follows:

     D ReasonDS        ds                  qualified dim(200)
     D  @RsnCode                      2A
     D  @Charge                       9P 2
     D  @Weight                       9P 0
     D  @Units                        7P 0

In this case, it actually *is* an array of data structures. You have oneDS with 4 subfields, and 200 copies of that DS. The only problem withthis technique is that RPG won't let you use BIFs like %LOOKUP, orop-codes like SORTA on the array, which some people find to be adisadvantage. Personally, I don't mind coding my own functions toreplace %LOOKUP and SORTA, so it doesn't bother me.