Backing out work

If an error occurs within a unit of recovery, WebSphere MQ removes any changes to data, returning the data to its state at the start of the unit of recovery; that is, WebSphere MQ backs out the work. The events are shown in Figure 13.

Figure 13. A unit of recovery showing back out
A diagram illustrating a unit of recovery showing back out. In this example, page sets are being updated, but then the updates are backed out, and data is returned to its initial state. The unit of recovery starts just before the page set updates, and ends at the point where the data has been returned to its initial state.