Excessive EXCPS (I/Os)
If your job executing a map or systems of maps seems to generate an excessive amount of EXCPS (Execute Channel Programs) (I/Os), there are a number of items you can immediately examine and correct to improve by reducing the total EXCPS.
The following table lists some recommendations to make better use of resources required for a particular map executed, along with the references to additional documentation:
- Recommended Action
- Documentation Reference For Batch Execution Environment
- Identify and verify that the output data sets that your map (or maps) generates are being created using a system-determined block size.
- Output Data Sets (Target)
- Identify and verify that your input data sets are using optimum block sizes.
- Input Data Sets (Source)
- Statically allocate, use VIO for temporary data sets, set LRECL=32760 and set RECFM=FBS on their definitions.
- Temporary Data Sets (Work Files)
- Calculate new WorkSpace PageSize size:count settings based upon your maps work. Increasing the amount of available paging memory can reduce EXCPs.
- Execution Command Settings
- Use striped data sets if applicable and available.
- Striped Data Sets
- Examine the usage of the -WM (Work Files in Memory) option.
- Execution Command Settings
- Examine the usage of the -WH (Work Files in Memory - Hiperspace) option.
- Execution Command Settings
- Proceed with any possible map tuning, if applicable.
- Map Performance Tuning Tips
- Install and run XPLINK load library version.
- XPLINK Performance Build