Locking (enqueuing on) resources in application programs

This topic describes locking (enqueuing) functions provided by CICS® (and access methods) to protect data integrity.

About this task

There are two forms of locking:
  1. The implicit locking functions performed by CICS (or the access method) whenever your transactions issue a request to change data. These are described under:
  2. The explicit enqueuing function that you request by means of an EXEC CICS command. This is described under Explicit enqueuing (by the application programmer).
Note: Locking (implicit or explicit) data resources protects data integrity in the event of a failure, but can affect performance if several tasks attempt to operate on the same data resource at the same time. The effect of locking on performance, however, is minimized by implementing applications with short units of work, as discussed under Dividing transactions into units of work.