RE: Commitment Control

Commitment control used to be a heavy burden on B-models, but those days
almost every HW configuration was constrained in some sense. Very often
B-configurations were disk-constrained, DASD were relatively expensive,
and nobody was especially eager to buy extra DASD to accommodate
journalling, one of the most important CC prerequisites. 

However strange that might seem, performance penalty one has to pay for
journalling without CC is much higher than that paid for journalling
with CC. Most of the applications use journalling one way or another.
Keeping transaction history is very important for almost every
commercial application, so be it IBM journals or application journals,
one must take this overhead into account too, and in my practice this
overhead has always exceeded the CC one. To preserve database integrity
lots of people update application journal files with FRCRATIO of 1, and
that is lot worse than CC.

Of course, CC must be properly implemented. Separate ASP for journals is
advisable, and sometimes it makes sense to implement it only for a few
of the most important application files. But most definitely the
categorical statement "I don't recommend CC on the 400, because it's too
heavy on the system" gives away either an old-timer or a
performance-illiterate person.

Lo

> -----Original Message-----
> From: John Hall [SMTP:jhall@hillmgt.com]
> Sent: 13 July 1998 12:47
> To:   MIDRANGE-L@midrange.com
> Subject:      Commitment Control
> 
> 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. 
> 
> We are on a Model 170 2164.  We just moved from an F10 so we can
> afford
> some overhead in processing time.
> 
> What is the general feeling on this ?  If we are posting a batch of
> 500
> records should we commit on every record, every 10th record or after
> the
> entire batch ?
> 
> I think it may be a case of lack of knowlege on his part but I would
> like some other opinions.
> 
> 
> John L. Hall
> Home Sales Co.
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