Default values of CAB buffering parameters
The default values for CAB buffering parameters RANSIZE, NBRSRAN, NBRDBUF, and OVERFLOW in IMS High Performance Unload are different from the default values used in DBT V2 HSSR.
The following table lists the differences of the default values of CAB buffering parameters.
| CAB parameter | Default value in IMS High Performance Unload | Default value in DBT V2 HSSR |
|---|---|---|
| RANSIZE | Automatically determined from the characteristics of database data set | 8 |
| NBRSRAN | 8 | 4 |
| NBRDBUF | Twice the number assigned to RANSIZE | 4 |
| REFT4 | Equals to RANSIZE | 12 |
| OVERFLOW | CAB | BB |
If your JCL for DBT V2 HSSR uses the default values for CAB buffering parameters, running the job on IMS High Performance Unload might require more storage.
To avoid this storage problem, the function to fallback the default values to the ones that are compatible with DBT V2 HSSR is provided. For details, see Site default options.