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GeminiK_80 · Beginner Joined: 26 Apr 2005 Posts: 7 Topics: 3

Hi!
This is my first post to the forum. I have a question in IMS/DC which I donot know.
There are some online systems in our shop that allow us to access and update IMS/DB2 databases using IMS/DC.

Can anyone please let me know the resources that an MPP consumes
a) when transactions are in progress. i.e. someone is updating the database using onlines.
b) when no transactions are happening

I guess they might be usine some IMS control regions but it would be great if you tell me a way to quantify it (sayin terms of CPU time). Let me know if was not clear.

Thanks in advance.
Gemini K.
_________________
Thanks,
Gemini K.

Bithead · Posted: Wed Apr 27, 2005 8:16 am Post subject:

It would be very hard to give an estimate of the actual resource usage for an IMS TM (Transaction Manager) installation as it is dependant on the number of transactions, what the programs are doing and the IMS configuration.

IMS TM has a minimum of 4 address - The control region, the DLI subsystem, the DBRC subsystem and one or more "online" or MPP regions. We run 15 MPP regions which is normally adequate for our thru-put.

We also run an IMS Connect address space to allow access from the web.

Quantifying CPU for a given region is also difficult. MPP non-database code executes in the MPP address space. Calls to full function IMS databases incur work in the DLI address space. Calls to DB2 incur work in the DB2 address space. This workload combines with IMS BMPs and any other DB2 calls making isolation of individual tasks difficult if not impossible.

GeminiK_80 · Beginner Joined: 26 Apr 2005 Posts: 7 Topics: 3

Hi Bithead!
Thanks for the reply. Okay, let me tell you my problem.
As I told you, we have an some online system using IMS/DC that allow us to access and update IMS/DB2 databases . These onlines are up 24x7.
We have decided to bring the onlines down during weekends since there is no activity in the weekends.

Now, we are curious to find whether this would save any resources or not. I am sure it would save. But what are those resources and is there a way to quantify it? If it doesn't save much, we may have to drop this idea of bring the onlines down.

Thanks in advance.
Gemini.
_________________
Thanks,
Gemini K.

Bithead · Posted: Wed Apr 27, 2005 1:58 pm Post subject:

It would probably save some resource but not much in my opinion. It depends on the size of your machine. It might free up one or more initiators though. It would also clean up memory which is probably more important.

I use weekend down time to run off-line reorgs and backups of databases and recons.

GeminiK_80 · Beginner Joined: 26 Apr 2005 Posts: 7 Topics: 3

Thanks again for your quick reply.
What initiators are you talking about?
Can you please tell me what resources it could save in detail?
_________________
Thanks,
Gemini K.

Bithead · Posted: Wed Apr 27, 2005 3:36 pm Post subject:

The control region and MPP regions can be run as jobs rather than started tasks. If they run as jobs then they use initiators.

If your IMS TM installation is running idle then you would be mostly saving CPU with an occasional amount of I/O.