RE: Journaling

["Shaw, David" <dshaw@xxxxxxxxxxx>]

David,

Like Simon, I don't understand why you think reads are (or were) ever
journalled.  I suspect that it's really record locks when using commitment
control that you're concerned with.  If I'm not mistaken, commitment control
honors read-without-locking on update files, but of course MacPac's coding
for commitment control was done years before that became available in RPG.

Regardless of that, I concur that the myth of journalling bringing an AS/400
to its knees is exactly that - a myth.  I journalled all the files in MAPICS
for many years without any problems, and MAPICS is definitely NOT written
with journalling or commitment control in mind (except for the International
Financial Module, of course, which we didn't have).  The only thing I ever
worried about was making sure that I didn't have more journal receivers
on-line than my DASD capacity could handle comfortably (and I did have to
size my DASD with the receivers in mind).  Unfortunately, I've never come
across any benchmarks on it - all I can offer is additional hearsay
testimony.

Dave Shaw
Spartan International, Inc.
Spartanburg, SC

-----Original Message-----
From: Simon Coulter [mailto:shc@flybynight.com.au]

Hello David,

You wrote:
>But - Andersen bothered to build in the journaling properly.  Part of this
>is to open files for input only where possible.  Files opened for update
>will have all their reads journaled.  So... MACPAC would often open the
same
>file multiple times - once for read only operations, once for updates.
This
>minimized the impact on the journals.

While I agree with most of what you wrote, this statement is silly.  READs
are never 
journalled, what would be the point!  I know some sites want to know who
read a record 
but journalling isn't the way to accomplish that.  Journalling has no effect
on reads.  
Even reads though an update ODP.

Regards,
Simon Coulter.

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