This section contains instructions for coordinating threads and re-partitioning the workload among new or different threads. A coordinated Replicat should be stopped cleanly with the STOP REPLICAT command before making modifications to the partition specifications in THREAD or THREADRANGE clauses of the MAP statements. A clean stop ensures that all of the threads, which may be at different locations in the trail at any given point, all finish their work and arrive at a common trail location.

At startup, Replicat issues an error and abends if it detects that the last shutdown was not clean and the partitioning in the MAP statements was changed to contain a different number of threads (threads were added or removed). However, if the same threads are kept in the parameter file but simply rearranged among different MAP statements, Replicat issues a warning but does not abend. This can result in missing or duplicate records, because there is no way to ensure continuity of the thread-to-workload allocations from the previous run.

The following is an example of this condition.

Following is the original partitioning scheme:

MAP source, target, THREADRANGE(1-5);
MAP source1, target1, THREADRANGE(6-10);

The following re-partitioning of the original scheme produces only a warning:

MAP source, target, THREADRANGE(1-4);
MAP source1, target1, THREADRANGE(5-10);

This section provides instructions for cleanly shutting down Replicat before performing a re-partitioning, as well as instructions for attempting to recover Replicat continuity when a re-partitioning is performed after an unclean shutdown.

The following tasks can be performed for a Replicat group in coordinated mode.