From: Vohs, Bill
Sent: Wednesday, February 01, 2006 2:09 PM
Subject: Question: Why Severe Performance Degradation after
From: Bill Vohs, SC Data Center, Monroe, Wi
Date: February 1, 2006
Subject: Enlarge/Expand IDMS Database
We are running:
IDMS Release 16 SP02
EMC DMX2000 DASD
We have a need to enlarge a number of the IDMS databases.
Every time we do, we experience a severe performance degradation.
Run times elongate by a factor of 3 to 5.
Our first attempt was back in November.
The approach at that time was to do an UNLOAD and RELOAD to enlarged
area. This time the databases were enlarged by a factor of 3.
One database went from 15,000 tracks on a 3390 to 45,000 tracks.
Another database went from 7,000 tracks to 21,000 tracks.
Our run times were:
Before UNLOAD/RELOAD 11/09/2005 74
11/10/2005 46 minutes
After UNLOAD/RELOAD 11/16/2005 174
11/1/2005 198 minutes
Our second attempt was January 29, 2006..
The approach for this time was to do a EXPAND PAGE to enlarged area
This time the databases were enlarged by a factor of 2.
One database went from PAGE SIZE 5064 to 10796 from 15,000 tracks to
30,000 tracks. Another database went from PAGE SIZE 5064 to 10796 from
7,000 tracks to 14,000 tracks.
The run times are:
Before EXPAND PAGE 01/26/2006
After EXPAND PAGE 01/31/2006
02/01/2006 212 minutes
We have had an IDMS consultant review our work and he says every thing
Our z/OS and IDMS statistics show nothing out of the ordinary.
We are at a bit of a loss.
Might anybody have any suggestion for us?