If the secondary database has been opened in an environment configured with transactions, the entire secondary index creation is performed in the context of a single transaction.

Care should be taken not to use a newly-populated secondary database in another thread of control until Open(String, SecondaryDatabaseConfig) has returned successfully in the first thread.

If transactions are not being used, care should be taken not to modify a primary database being used to populate a secondary database, in another thread of control, until Open(String, SecondaryDatabaseConfig) has returned successfully in the first thread. If transactions are being used, Berkeley DB performs appropriate locking and the application need not do any special operation ordering.