ca.portal.admin

Re:Performance Degradation after Database Enlarge/Expand

Discussion created by ca.portal.admin on Feb 8, 2006
From: Bill Vohs, SC Data Center, Monroe, Wi
Date: February 1, 2006

Subject: Enlarge/Expand IDMS Database Causes Severe Performance
Degradation

We are running:

z/OS 1.4
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 severe performance degradation.
Run times elongate by a factor of 3 to 5.
Job that ran in 30 minutes now takes 3-4 hours.

Our first attempt was back in November 2005.
The approach at that time was to do an UNLOAD and RELOAD to the enlarged
area.
This time we enlarged the databases by a factor of 3.
I.e. One database went from 15,000 tracks to 45,000 tracks.
Another database went from 7,000 tracks to 21,000
tracks.
These all on 3390 DASD on the EMC DMX2000.

Our run times were:

Before UNLOAD/RELOAD 11/09/2005 74
minutes
11/10/2005 46 minutes

After UNLOAD/RELOAD 11/16/2005 174
minutes
11/1/2005 198 minutes

This happened with almost every one of our jobs.

Our second attempt was January 29, 2006..
The approach this time was to do a EXPAND PAGE to an 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
64
minutes

After EXPAND PAGE 01/31/2006
209
minutes
02/01/2006 212 minutes


We have had an IDMS consultant review our work and he says every thing
looks
great.

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?

"
IDMS Public Discussion Forum
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Normal

Normal
Re: Performance Degradation after Database Enlarge/Expand
"Larger area results in longer times for area-sweeps..
Did you increase the buffer-size to 10796 as well as adding to it's
numb-pages? A mismatch is just wasted.
Sometimes a new buffer 'just' for this area can be beneficial, although
subtracts from the whole available.
I can't ever get the new buffer to 'take' until I recycle the CV, even
though it reports it's there,
it's not effective until a recycle.
Also, do you hard-code the run CV's memory instead of recommended
REGION=0M ??
BTW, I get a bit better use of 11476 than 10796 for some reason.

Good luck and do keep the List posted on your efforts.

vohs@SCDATACENTER.COM 02/08/06 2:03 PM >>>
From: Bill Vohs, SC Data Center, Monroe, Wi
Date: February 1, 2006

Subject: Enlarge/Expand IDMS Database Causes Severe Performance
Degradation

We are running:

z/OS 1.4
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 severe performance degradation.
Run times elongate by a factor of 3 to 5.
Job that ran in 30 minutes now takes 3-4 hours.

Our first attempt was back in November 2005.
The approach at that time was to do an UNLOAD and RELOAD to the
enlarged
area.
This time we enlarged the databases by a factor of 3.
I.e. One database went from 15,000 tracks to 45,000 tracks.
Another database went from 7,000 tracks to 21,000
tracks.
These all on 3390 DASD on the EMC DMX2000.

Our run times were:

Before UNLOAD/RELOAD 11/09/2005 74
minutes
11/10/2005 46 minutes

After UNLOAD/RELOAD 11/16/2005 174
minutes
11/1/2005 198 minutes

This happened with almost every one of our jobs.

Our second attempt was January 29, 2006..
The approach this time was to do a EXPAND PAGE to an 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
64
minutes

After EXPAND PAGE 01/31/2006
209
minutes
02/01/2006 212 minutes


We have had an IDMS consultant review our work and he says every thing
looks
great.

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?

"
IDMS Public Discussion Forum
IDMS-L@LISTSERV.IUASSN.COM
SMTP
IDMS-L@LISTSERV.IUASSN.COM
IDMS-L@LISTSERV.IUASSN.COM
SMTP








Normal

Normal
Re: Re. Performance Degradation
"As mentioned below, we experience the same problem a year ago not
unloading/reloading all the member records which did not have owner
pointers. After the unload/reload, the batch execution of those areas
went from 30 minutes to over 6 hours. We solve the problem by unloading
and reloading the entire dataset and then subsequently adding owner
pointers to the sets that did not have them.

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