Re: Commitment Control

[DAsmussen@xxxxxxx]

John,

In a message dated 98-07-13 09:54:27 EDT, you write:

> We are in the midst of doing some conversions to old software.  One of
>  the programmer/consultants we brought in is arguing against setting up
>  commitment control.  I feel that it is a feature we should be using. 
>  
>  He feels that there may be too much overhead on the system.  We are
>  going to enable journaling on all these files anyway. 
<<snip>>

Most of the overhead involved with commitment control is due to the
journaling, which you plan to do anyway.  However, you should note that even
if you are journaling only "after" images it automatically switches to "both"
for files opened under commitment control.  The biggest problem with
commitment control on the AS/400 is the code involved.  You have to:

1)  Establish the commitment control environment for the job with a CL
command.
2)  Change all programs that need it to open update/output files under
commitment control.
3)  Monitor UPDAT and WRITE commands for failures more stringently than most
"legacy" code does, to facilitate a ROLBK.
4)  Beware called API's that may update files from within the commitment
environment.
5)  Add an error handling routine to your code (if not already there) to
perform the ROLBK should an unexpected failure occur -- if you don't ROLBK the
changes will be COMIT'd _for you_!

IMO, commitment control performance issues are left over from "the old days"
when DASD was expensive and slow.  My big gripe is that implementing CC on the
AS/400 is not as easy as it is on a mainframe or, say, Oracle-based system.
Of course, IBM has no incentive to improve its' implementation because
everyone still thinks its' too big a performance hog to use.  Can you say
"Deadly Embrace"?

JMHO,

Dean Asmussen
Enterprise Systems Consulting, Inc.
Fuquay-Varina, NC  USA
E-Mail:  DAsmussen@aol.com

"Jimi Hendrix was the first rocker on the Internet - his modem was a purple
Hayes." -- Anonymous
+---
| This is the Midrange System Mailing List!
| To submit a new message, send your mail to MIDRANGE-L@midrange.com.
| To subscribe to this list send email to MIDRANGE-L-SUB@midrange.com.
| To unsubscribe from this list send email to MIDRANGE-L-UNSUB@midrange.com.
| Questions should be directed to the list owner/operator: david@midrange.com
+---