The synchronization parameter controls whether the COMMIT order in the captured workload will be preserved during replay.
If this parameter is set to SCN, the COMMIT order in the captured workload will be preserved during replay and all replay actions will be executed only after all dependent COMMIT actions have completed.
If this parameter is set to OBJECT_ID, all replay actions will be executed only after all relevant COMMIT actions have completed. Relevant COMMIT actions must meet the following criteria:
Issued before the given action in the workload capture
Modified at least one of the database objects for which the given action is referencing, either implicitly or explicitly
Setting this parameter to OBJECT_ID allows for more concurrency during workload replays for COMMIT actions that do not reference the same database objects during workload capture.
You can disable this option by setting the parameter to OFF, but the replay will likely yield significant replay divergence. However, this may be desirable if the workload consists primarily of independent transactions, and divergence during unsynchronized replay is acceptable.