Tuning Your Applications › Resource Conflict Delays

Resource Conflict Delays

This section describes the various types of resource conflict delays, and the possible reasons for them.

Data set in use by another application

Indicates one of the following reasons:

When jobs are executed concurrently, z/OS provides data integrity by using system-wide enqueues.

If a job allocates a data set by using DISP=SHR, it has concurrent access, but each program must ensure data integrity. If a job allocates a data set by using DISP=OLD, the z/OS operating system provides data integrity and requires all other programs to wait until the data set is free.

Reduce resource conflicts by ensuring that jobs use the same resources in a serial manner.

Logical resources in use by another application

z/OS provides the ENQUEUE/DEQUEUE facility to ensure that logical resources are protected when multiple jobs or tasks require serialization.

For example, when the program uses the ENQUEUE facility to provide a queueing function for a server task, the requesting tasks waiting in ENQUEUE are delayed.

Reduce resource conflicts, caused when queueing is emulated with the ENQ/DEQ services, by using another queueing algorithm.