ca.portal.admin

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?
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Normal

Normal
Re: Performance Degradation after Database Enlarge/Expand
"Hi Bill,

Unless I am missing something in your performance
scenario, I don't see the kind of info one needs to help
you with this problem; for a start, if I was an IDMS
Consultant that says everything looks great, I would
'then' be looking at and asking for as a minimum:

- An IDMSDUMP-type report that lists the IDMS record
types, number of IDMS areas and distribution of
records.Are there indices in this dataset? What is the
area to file mapping for this dataset? CALC records?

- RMF reports; where is all the I/O time, wait time, CPU
being spent?

-do you have a idms specific performance monitor (or
DCMT)that you use to monitor the programs? Are they
waiting on any resources?

-What do these applications 'do' that access these
datasets? Do they update? Update indices? walk sets?

-DMCL info for the files, areas, and buffers that map to
these datasets? Do you have original page size or page
reserve-type clauses specified here?

-And last but not least, what release of IDMS and your
maintenance level?

I hope this helps at least point out that the problem
could be related to any number of things!

regards,
Joe Perkins



-On Wed, 8 Feb 2006 13:03:25 -0600
""Vohs, Bill"" <vohs@SCDATACENTER.COM> wrote:
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: Performance Degradation after Database Enlarge/Expand
"Sorry Bill,
I see that you are IDMS 16......

Joe Perkins
On Wed, 8 Feb 2006 13:03:25 -0600
""Vohs, Bill"" <vohs@SCDATACENTER.COM> wrote:
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: Performance Degradation after Database Enlarge/Expand
"You didn't mention the type of jobs that were experiencing performance
problems. But if they are doing area sweeps they will of course run
longer. I would suggest that you use prefetch with file buff parm set
to at least 3000. If the jobs are using indexes perhaps a rebuild
would help. That's about all I can say based on the limited information
supplied.

Dan Miley
Lockheed Martin

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