Few Nonstop Fundamentals - V

CHECKPOINT

A checkpoint is a Nonstop specific Term relevant only to Nonstop Process Pairs. The purpose of a checkpoint is to ensure that the two process have identical process state so that if there is a single point of failure, the backup process can take over the completion of processing  without the requesting process needing to do any exception handling.

The purpose of checkpoints are to make primary process failures transparent.

Checkpoints occur on critical region boundaries to ensure all-or-nothing processing process semantics.

The primary process sends checkpoints on critical region boundaries to the backup and waits for acknowledgement before proceeding to the next critical region step.

Its upto Application Architects to determine what the critical regions of a process are.