Chapter 8 Creating J2EE Applications for BEA WebLogic
The EJB container in WebLogic Server can use exclusive locking mechanism for entity EJB instances. As clients enlist an EJB or EJB method in a transaction, when using exclusive locking, WebLogic Server places an exclusive lock on the EJB instance for the duration of the transaction. Other clients requesting the same EJB or method are blocked until the current transaction completes.
Exclusive locking was the default in WLS 5.1 and 4.5.1. This method of locking provides reliable access to EJB data, and avoids unnecessary calls to ejbLoad() to refresh the EJB instance's persistent fields. However, exclusive locking does not provide the best model for concurrent access to the EJB's data. Once a client has locked an EJB instance, other clients are blocked from the EJB's data even if they intend only to read the persistent fields.
| Copyright (C) 2005. Sybase Inc. All rights reserved. |
| |