When a replica is in the process of synchronizing with its master, all DB operations are blocked until such a time as the synchronization is completed. For replicas with a heavy read load, these blocked operations may represent an unacceptable loss in throughput.

You can configure DB so that it will not block when synchronization is in process. Instead, the DB operation will fail, immediately returning a DB_REP_LOCKOUT error. When this happens, it is up to your application to your application to determine what action to take (that is, logging the event, making an appropriate user response, retrying the operation, and so forth).

To turn off blocking on synchronization, specify DB_REP_CONF_NOWAIT to DbEnv::rep_set_config() and then specify 1 to the onoff parameter. (Specify 0 to turn the feature off.)