Learn the processes involved and the status of the components in a warm standby enviroment before you switch from the active to the standby database.
This figure illustrates the normal operation of an example warm standby application.
Replication Server writes transactions received from the active database into an inbound message queue.
See Replication Server Administration Guide Volume 1 > Replication Server Technical Overview > Transaction Handling with Replication Server > Distributed Concurrency Control for more information about inbound and outbound queues.
This inbound queue is read by the DSI thread for the standby database, which executes the transactions in the standby database.
Messages received from the active database cannot be truncated from the inbound queue until the standby DSI thread has read them and applied them to the standby database.