This figure shows the lifecycle of test master and snapshot databases.

A production database points to a Data Guard Replica. Step 1 converts the Data Guard replica to a test master database. In this step, defer redo transport, convert to Data Guard snapshot standby, prepare to be the test master database, close the database, and open it read-only.

Step 2 is create snapshots to use for development and testing.

Step 3 is refresh test master database. In this step, drop snapshots, convert Data Guard snapshot standby back to original state, apply RMAN incremental from production to refresh the Data Guard replica, enable redo transport to complete the resynchronization process. Then start again at step 1.