Grouping application transactions in DB/DC and DCCTL environments
When you group transactions and associate them with a particular message class and region, the criteria you use to group them can include virtual storage considerations, PSB characteristics, and priority of service.
You must associate different groups of transactions with a particular message class that can be assigned to a region. (Batch message programs are allocated in their own region.) Criteria might be the virtual storage the message processing programs require, the PSB characteristics they share, or the priority of service for the end user. Lay out the transactions in a summary matrix. An example of this information summary for a vehicle routing application is shown in Table 1.
| Transaction Group | Transaction Code | Transaction Rate | Program | Preload | REGN | Processing Mode |
|---|---|---|---|---|---|---|
| Driver log | TRLOG | 1000 /day | PGMA | - | 520 KB | SINGLE |
| Driver changes | TRCHG | 300/hr | PGMB | PRLD | 200 KB | MULTIPLE |
| Enter load or job | TRLOAD | 50/hr | PGMC | - | 520 KB | CONVERSATION |
| Status of job | TRSTAT | 20/hr | PGMD | - | 520 KB | SINGLE |
| Optimize route | TROPT | 10/day | PGME | - | 400 KB | (SINGLE) BMP |
| Get driver route | TRROUT | 50/hr | PGMF | - | 100 KB | SINGLE |
One solution for this group of transactions is to define a message class for TRLOG, TRLOAD, and TRSTAT, which seem to be frequently used, and assign them to a message region. The BMP has its own region. The driver control transactions, TRCHG and TRROUT, can be assigned to another message class, because they have similar virtual storage requirements and one of them needs the program preload function specified on the region JCL.
The process of grouping transactions becomes more complex when you have competing application programs. An additional factor to consider is the database processing intent. You should attempt to combine compatible application programs (such as application programs that are inquiry only) into groups before assigning them a message class and individual priorities.