RE: RPG enhancement suggestion

[Buck Calabro <mcalabro@xxxxxxxxxxxx>]

This is what I learnt about what happens (roughly) when RPG does a
READx/CHAIN from S/38 days:
1. Database manager fetches record to internal buffer (this may happen
asynchronously)
2. Database manager gives record to RPG buffer (ZZ01BIN et. al.)
3. RPG maps/converts data from internal buffer to field storage - one for
each field in the record.

If you were to use a logical or SQL view that contained only the fields you
needed, then things would go faster.  The database manager would be moving
fewer bytes/request, and RPG would be mapping fewer fields/request.  I
suspect the RPG time is the slowest of the components, and would see the
most improvement from a shorter record.

I can't tell if the unreferenced fields get mapped or not; if I specify H
DEBUG, they do.

This may turn into one of those "which is faster: Z-ADD vs MOVE" threads.
The rule that I follow is to not worry about it unless I'm fetching a few
huge records or millions of any records.  Make it right, then make it fast.

Buck Calabro

> -----Original Message-----
> From: Colin Williams 
> Sent: Monday, June 21, 1999 11:15 AM
> To:   'RPG400-L@midrange.com'
> Subject:      RPG enhancement suggestion
> 
> 
> I have been writing an extract program, to bring in data from a file on
> an external system. During this, a question occurred.
> 
> Would file processing in RPG be a lot quicker if we could drop fields
> that we weren't using, similar to the way it works when you internally
> describe
> a file, but without actually decribing the file internally.
> 
> eg: if I have a typical input file with 50 fields on it, but I only
> actually use 1 field on it in the program, I would like a keyword that
> allows me to
> drop all the other fields from the file.
> 
> 
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* This is the RPG/400 Discussion Mailing List!  To submit a new         *
* message, send your mail to "RPG400-L@midrange.com".  To unsubscribe   *
* from this list send email to MAJORDOMO@midrange.com and specify       *
* 'unsubscribe RPG400-L' in the body of your message.  Questions should *
* be directed to the list owner / operator: david@midrange.com          *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *