30.4.7. Running Within a Cluster

Currently there is no distributed locking capability for entity beans within the cluster. This functionality has been delegated to the database and must be supported by the application developer. For clustered entity beans, it is suggested to use commit-option B or C in combination with a row locking mechanism. For CMP, there is a row-locking configuration option. This option will use a SQL select for update when the bean is loaded from the database. With commit-option B or C, this implements a transactional lock that can be used across the cluster. For BMP, you must explicitly implement the select for update invocation within the BMP's ejbLoad method.