Poor response time: Causes and solutions
This table shows four levels of response time, in decreasing order of severity. The major causes are shown for each level, together with a range of suggested solutions.
The first step is to check the causes by following the advice given in Assessing the performance of your system. When you have identified the precise causes, you can find information in Improving the performance of a CICS system on how to implement an appropriate solution.
| Major cause | Solution |
|---|---|
| Level 1: Poor response at all loads for all transactions | |
| High level of paging | Reduce working set, or allocate more real storage |
| Very high usage of major resources | Reconsider system resource requirements and redesign system, and check for application errors and resource contention |
| Level 2: Poor response at medium and high loads | |
| High level of paging | Reduce working set, or allocate more real storage |
| High processor usage | Reduce pathlength, or increase processor power |
| High DB or data set usage | Reorganize data sets, or reduce data transfer, or increase capacity |
| High communication network usage | Reduce data transfer, or increase capacity |
| TP or I/O access-method constraint | Increase buffer availability |
| CICS limit values exceeded | Change operands, or provide more resources, or check if errors in application |
| Level 3: Poor response for certain transactions only | |
| Identify common characteristics listed under Level 2 | The solutions are as for Level 2 |
| Lines or terminal usage | Increase capacity, or reduce data transfer, or change transaction logic |
| Data set usage | Change data set placement buffer allocations or change enqueue logic or data set design |
| High storage usage | Redesign or tune applications |
| Same subprograms used by transactions | Redesign or tune application subprograms |
| Same access method or CICS features used by transactions | Reallocate resource or change application, and reevaluate use of feature in question |
| Limit conditions | Reallocate resource or change application |
| Level 4: Poor response for certain terminals | |
| Check network loading as appropriate | Increase capacity of that part of network |
| Check operator techniques | Revise terminal procedures |
| Check terminal definitions | Redefine terminal definitions |