There are many occasions to forward data from one database to another: usage of more economic platforms for subordinate processing, improved accessibility, fault tolerance, conversion projects, etc. In general propagation is a well defined task; at the beginning the data must be entirely copied to the target system and afterwards periodically synchronized, in other words, the changes that occur at the source side need to be forwarded or propagated to the target from time to time. The process is of course asynchronous, the source does not wait for the target’s acknowledgement.
As the DB2 Log records all data changes, it is ideally suited as a base for the provision of the updates that occurred on the source side of the process to the tables in question. The challenge lies in the synchronization of the initial load and the subsequent ongoing propagation of the deltas, and, as always, in the operational requirements regarding a robust, easily restartable and flexible process. Flexible for example in respect of scope changes, i. e. additional or other tables and also in respect of table structure changes.
Most qualified for robust propagation is a tool that helps with automations for table creation, initial copy and synchronization, scope changes and structural alters, and last but not least, that ensures gap-less update of the target tables.