How the Data Propagator replication engine handles data changes to the source system

When the source application changes a table in the source system, the changes are synchronized Data Propagator replication engine first captures the changes, synchronizes them to the mirror system, and then applies them to the target system (the mobile device).

This process is illustrated in the following figure:

Figure 1. The process that the Data Propagator replication engine uses to handle changes to the source system

1. The source application makes changes to the source tables.
2. The DB2 transaction log saves the changes.
3. The capture process on the source system asynchronously reads the changes from the logs and captures them to the change data tables.
4. The Data Propagator apply process reads the changes from the change data tables and applies them to the mirror tables on the mirror system. There is no lock activity on the source tables during this process.
5. The DB2 transaction logs saves these changes.
6. The capture process on the mirror system reads the changes from the logs and captures the changes to the change data tables. DB2 Everyplace ensures that the capture process on the mirror system is run asynchronously at the start of replication.
7. The replication engine reads from the change data tables and updates the changes to the history tables.
8. The next time a client synchronizes, the changes are sent from the history tables to the client tables.