Configuring Change Data Capture

Oracle recommends that Change Data Capture (CDC) is configured and started before the Initial Load. This enables "change synchronization" to keep track of ongoing transactional changes while the load is being applied—a very useful feature when you cannot afford for your source system to be taken offline. In fact GoldenGate can manage and combine the online transactional changes plus the initial data extract with ease, ensuring no data loss or down-time.

So let's take a look at the steps required to configure and start CDC.

As stated in Chapter 1, the Extract process extracts only committed transactions from the database's redologs. The first task, therefore, is to create the Extract process.

1. Log on to the source database server (as oracle).

2. Change directory to the GoldenGate home.

   cd /home/oracle/ggs
   

3. Start GGSCI.

4. Execute the following commands on the source system to create a parameter file for the Extract process named EOLTP01:

   GGSCI (dbserver1) 1> EDIT PARAMS...