Queued transaction processing with web service reliable messaging

Abstract

With the popularity of the distributed business applications, the application data is distributed in various physical storages. However most of the business transactions require to update data stored in more than one storage. hence updating two data storages reliably is a common problem for most of the distributed business applications. Queued transaction processing is a concept widely used to achieve such a processing model using intermediate queues to transfer messages reliably. In such a system at the client side, both updating the client storage and writing the message to be sent to the client side message queue happens in the same distributed transaction. Similarly at the server side reading the message from the server side queue and updating the sever storage happens in the same distributed transaction. Bur such a system may have interoperability problems if client and server use different types of technologies. Web services are used to communicate among the heterogeneous systems by passing SOAP messages using standard transport mechanisms like http. Web services can reliably communicate by using WS-Reliable messaging specification(WS-RM). WS-RM uses concepts of Reliable messaging source (RMS) and Reliable messaging destination ( RMD) between which it guarantees reliable massage delivery. By combining these two concepts, we introduce an approach to solve the above mentioned problem in an interoperable manner using WS-RM ..,to communicate between nodes while keeping RMS and RMD as intermediate storages. In our model reliable message delivery happens in three phases. First both updating application client storage and writing message to the RMS happens in the same distributed transaction. Then WS-RM protocol reliably transfers the message to RMD at the server side . Finally- at the server reading the message from the RMD and updating the server storage happens in the same distributed transaction. The middleware software entity that we developed to encapsulate this approach is called Mercury which implements WS-RM protocol.