X / Open XA ( XA short ) is a specified by the Open Group standard computer science for Distributed Transaction Processing, the execution of distributed transactions across multiple systems. Using the XA standards, various resources ( such as databases, application servers, messaging systems ) are addressed within a transaction, while preserving the ACID properties of transactions.
The Open Group document Distributed Transaction Processing: The XA Specification describes what needs to provide a resource manager to allow accordance with XA distributed transactions. Thus, the procedure and the interface between the global transaction manager and the local resource managers is set. Resource managers that meet the standard are called "XA compliant". The XA standard is based on the two- phase commit protocol.