RE: This way or that?

["York, Albert" <albert.york@xxxxxxxxxxxxxx>]

One of the few valid reasons for using multi-member files is that chunks of
related data can be easily deleted. All you have to do is remove or clear
the member. If you put the data in one big member, keyed by device ID, then
cleanup becomes a purge process, where you have to read through the file and
delete the records one at a time. The only way to get rid of the resulting
deleted records is to reorganize the file, or change the file to reuse
deleted records, which can have it's own problems.

I think (in this case) a multi-member file is the right way to go, but only
if the member is cleared or removed when the user signs off. If the users
complain that this takes too long then submit a job to batch so the cleanup
happens after they sign off or simply clear all members at night. 

Albert York

 
-----Original Message-----
From: Graap, Ken [mailto:keg@exchange.gasco.com]
Sent: Friday, June 09, 2000 1:30 PM
To: 'Midrange'
Subject: This way or that?


Question - 

We have a process that adds a member (member name=device name) to a file
which is then used as a work file for the current job. Once a member has
been added it is never cleared or removed.

At any time there may be as many as 500 members in this file and each member
may contain several thousand records (1,000 - 50,000).

There are also several logical views defined over this file. The first view
has 6 formats and three other views have one each. So at any one time there
can be up to 2000 indexes all defined with Access Path Maint *IMMED. 

When everything is added up, this 'work file' takes up 259MB of disk space
for data and 814MB of disk space for indexes. A total of over 1GB. 

The developer who designed this process says that he doesn't remove these
file members when a user signs off  in order to avoid the overhead of adding
a member each day when a user starts an application session.

If you were designing this application to optimize the use of system
resources (disk utilization, program performance, backup recovery etc) would
you remove these work files daily and add new members when needed or would
you leave the work files in place as we are doing?

I'm looking forward to all your thoughts....

Kenneth

****************************************
Kenneth E. Graap
IBM Certified Specialist
AS/400 Professional
Network Administrator
NW Natural (Gas Services)
keg@nwnatural.com
Phone: 503-226-4211 x5537
FAX:    603-849-0591
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