RE: Journaling... Help me understand

["Walden H. Leverich III" <WaldenL@xxxxxxxxxxxxxxx>]

Think of them as an _efficient_ copy of every change you make to a file.
They're required for commitment control (without it how would the machine
know what the row used to look like), and useful for other things. 

There are two reasons people usually use journals: 1) Support commitment
control and access path rebuilds and 2) Audit

In the first case I'd setup journaling so the machine attaches new receivers
as needed and deletes the old ones. You don't care that they exist, it's the
machine that needs them. 

In the second case I'd still setup journaling so the machine attaches a new
journal receiver as needed but obviously you can't delete it until it's
saved somewhere. 

Oh, that brings up the difference between journals and journal receivers.
The journal is a big funnel that the system throws things into. The Receiver
is the bucket that the funnel dumps stuff into. You can put new buckets
under the funnel when the old buckets are full, that's called changing the
receiver.

-Walden


------------
Walden H Leverich III
President & CEO
Tech Software
(516) 627-3800 x11
(208) 692-3308 eFax
WaldenL@xxxxxxxxxxxxxxx
http://www.TechSoftInc.com 

Quiquid latine dictum sit altum viditur.
(Whatever is said in Latin seems profound.)
 
-----Original Message-----
From: Wills, Mike N. (TC) [mailto:MNWills@xxxxxxxxxxxxxx] 
Sent: Tuesday, January 20, 2004 2:59 PM
To: Midrange Systems Technical Discussion
Subject: Journaling... Help me understand

Is there a book, a class, or just get general help about journals? I don't
understand them enough and now that we are starting to use them I feel I
should understand how to maintain and use them. I know that they record what
is changed in the file so that you can "back out" of a problem, but beyond
that I know little about them. Can anyone help me out on this? Thanks.

Mike Wills
Lawson Programmer/Administrator
Taylor Corporation
Email: mnwills AT taylorcorpNOSPAM DOT com
AIM: iSeriesCodePoet

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