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I have some questions about DB2 accounting reports:

1. Is all the CPU used by a batch DB2 job assigned to the job or is some of it assigned to a DB2 address space?

2. Do you have any suggestions for keeping track of DB2 CPU usage associated with these workloads?

Robert Catterall responds:

I wrote a DB2 DBA column on using DB2 accounting reports, which will be published in the Quarter 1, 2002 issue of DB2 Magazine, which will be online in February. In the meantime:

1. Depending on the nature of the database work being done by the batch program, I would say that the vast majority of the CPU time—probably well over 90 percent—is likely to be charged to the batch job's TCB. The rest would be mostly charged to DB2 and to OS/390. (Not all OS/390 services are charged to specific user programs. Some basically amount to operating system overhead.) Of the CPU time charged to DB2 address spaces, most would be charged to DB2 Database Services (also known as DBM1). This would be, among other things, CPU cycles expended in performing asynchronous database read and write operations related to the batch job's processing. A smaller amount of CPU time would be charged to the DB2 System Services address space (MSTR) for things like thread create and terminate processing.

2. I like to use DB2 monitor accounting detail reports for this purpose. I would group the data by correlation ID (this can be done via control statements in the batch job that generates the accounting report). I believe that this would provide you with data grouped at the transaction ID level (for CICS transactions) and at the batch job level.

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