Quick reschedule for regions in DB/DC and DCCTL environments

Quick reschedule allows application programs to process more than the processing limit of messages for each physical schedule. Quick reschedule eliminates processing overhead caused by unnecessary rescheduling and reloading of application programs.

When a region undergoes quick reschedule, the message count that is compared with the processing limit count is reset, the accounting (X'07') and scheduling (X'08') log records are written, and the next message is returned to the application program for processing.

A region can undergo quick reschedule only when:

• No other work of equal or higher priority exists for the region to process
• The same transaction would be scheduled if the application program terminated and the dependent region went through rescheduling.
• The region is an MPP processing a MODE=SNGL transaction
• The processing limit count is greater than zero
• The PSB is not allocated with the dynamic PSB option (DOPT)

Flags in the accounting and scheduling records written during a quick reschedule indicate that the records do not include actual program termination and scheduling times. These records are written for accounting purposes only. Restart and backout do not use these records.