RE: Optimizing File I-O in RPG IV/ I-Series

While I  believe you'll save something since the RPG program itself does less.

I don't believe you'll save as much as you think.  I believe the DB is smart 
enough to not update a record if nothing actually changes.

Testing confirms that update triggers are not fired nor are journal entries 
written with the following SQL

Update myfile
Set myfield = myfile


HTH,


Charles Wilt
--
iSeries Systems Administrator / Developer
Mitsubishi Electric Automotive America
ph: 513-573-4343
fax: 513-398-1121
  

> -----Original Message-----
> From: rpg400-l-bounces@xxxxxxxxxxxx 
> [mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Weber, Richard
> Sent: Wednesday, November 23, 2005 7:49 AM
> To: 'RPG programming on the AS400 / iSeries'
> Subject: RE: Optimizing File I-O in RPG IV/ I-Series
> 
> Maybe you're already doing this: Skip the update statement 
> for records whose
> data hasn't actually been changed.
> 
> Rick Weber  |  TOYS 'Я' US International 
> 
> -----Original Message-----
> From: Jim Wiant [mailto:Jim.Wiant@xxxxxxxxxxxxxxxx] 
> Sent: Tuesday, November 22, 2005 7:18 PM
> To: rpg400-l@xxxxxxxxxxxx
> Subject: Optimizing File I-O in RPG IV/ I-Series
> 
> We have a series of programs that update files for assorted 
> maintenance.
> The time these programs are taking is becoming excessive.
> 
> In most cases, the RPG code is very simple.
> 
> Key   SETLL                   file
> Key   READE                   file
>       (Do until EOF)
>       UPDATE          record
> Key   READE                   file
>       END DO
> 
> I don't see how the code can get might tighter. Is there any 
> reasonable
> compiling options/ CL overrides, etc. that could improve such 
> a routine
> when it
> needs to process a large number of records? We're not opposed to
> changing code, but if just a few H spec changes and/or 
> compiling options
> could gain
> us a bit of performance, it would help us out.
> 
> I've tried a few of the basics (OPTIMIZE(*FULL), NoDEBUGIO, etc.) but
> didn't see much of a change in my benchmarks.
> 
> Thanks for any help
> 
> Jim Wiant
> 
> 
> Once a job is fouled up, anything done to improve it makes it worse. 
> Finagle 
> 
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