Logical units of work
Log Analyzer organizes log information into logical units of work (LUOWs), which provide a more comprehensive, useful view of activities in your IMS systems than a simple unit of work (UOW) can provide.
A UOW is a familiar concept in the IMS environment:
- In an IMS database management (DB) environment, a UOW comprises all input and output messages that are associated with a transaction.
- In an IMS transaction management (TM) environment, a UOW comprises a single IMS message.
- In an IMS Shared Queues (CQS) environment, a UOW comprises a client-defined grouping of data objects.
The following figure shows typical activities in a transaction UOW. A message arrives in IMS and is placed on a message queue. The message is scheduled for execution. Application processing occurs, including DL/I database calls. All processing is completed, a sync point is taken, and an output message is sent.
Unit of work example
Log Analyzer identifies LUOWs to provide more powerful, meaningful insights into complex activities than a view of isolated UOWs can provide. An LUOW captures the entire application flow across boundaries of UOWs, message switches, IMS systems, sysplexes, and LPARs. Processing on non-IMS platforms is also represented in an LUOW to give you a complete view of the application flow.
The following figure shows typical activities in an LUOW.
Logical unit of work example
For this LUOW example, two sysplex environments have three logical partitions (LPARs). Sysplex A, with LPAR 1 and LPAR 2, is running the IMS1 system and the IMS2 system. Sysplex B, with LPAR3, is running the IMS3 system. A transaction can enter IMS from any of several sources, such as IMS/TM, IBM CICS-DB/CTL, or the web. Processing for this LUOW proceeds as follows:
- A transaction request (represented by UOW1) is issued to IMS1, and UOW1 is processed according to the UOW example.
- A message switch occurs to another transaction (represented by UOW2) that executes on IMS2. IBM DB2 access is performed in UOW2 before the transaction is completed.
- Another message switch occurs (represented by UOW3) to request information in IMS3. Processing in WebSphere for MQ is performed in UOW3.
- A final message switch occurs (represented by UOW4), and information is passed back to the originating IMS1. UOW4 is executed, and the results are returned to the requestor.