Research Of Resource Management In Transaction Processing Monitors

Transaction processing technology is a key technology to ensure reliability and consistency of information. The transaction processing monitor is a kind of middleware that specially provides this technology. It is the basic platform to explore, deploy, monitor, and manage three-tier online transaction processing applications, playing a crucial role in constructing transaction-based network distributed applications.Resource Managers are the important components in transaction processing monitors. They are the entities of transaction processing. The environment of distributed transaction processing often includes several resource managers. Transaction processing monitors are required to manage the transactions of these resource managers, controlling their participation in global transactions, and finishing transactions accurately. In addition, it is often time-consuming to access resource managers. And the interfaces they provide are often different. So transaction managers are also required to effectively manage resource accessing, improve the efficiency of applications, and provide uniform interfaces for them. These problems are the contents of resource management in transaction processing monitors. Research of these problems will help to improve the performance and scalability of transaction processing monitors, and bring convenience to application development.Based on the research of resource management in several widely used transaction processing monitors and relative standards, we design and implement the resource management modules at two different transaction systems. ISTX1.0 is a transaction service based on J2EE standard. It can provide JTS services for applications. And it can also be deployed into J2EE application servers, providing JTA interfaces for the latter. The resource management in ISTX1.0 takes a uniform management for all the databases connections, using connection pooling and reusing. This measure effectively improves the performance of applications and ISTX1.0. The resource management also implements part of the JCA1.0 standard. Thus, any EIS system keeping to this standard can be easily added into ISTX1.0. In addition, the resource management module combines with that of transaction processing, fulfilling the functions of resource enlist and delist in transaction managers. Several design patterns are used in the coding process. So the architecture of resource management is very obvious and easy to manage.ISTX2.0 is a transaction processing monitor based on X/Open Distributed Transaction Processing model. It could be working at several different platforms including Windows, Unix, Solaris, etc. ISTX2.0 implements load-balance inside. It can be used to construct key tasks and distributed enterprise applications of large-scale and high capacity. The resource management of ISTX2.0 is far away fromthat of ISTX1.0. It uses dynamic link libraries to uniformly manage all the resource managers in heterogeneous platforms. And it uses hooks to implement "same of thread", the method to check transaction contents in XA standard. These hooks also help ISTX2.0 support transfer of transactions in different processes. For all the connections of databases in ISTX2.0, resource management takes use of "once-connect, multiple-use", thus avoiding the connection pooling and reusing management. In addition, an idea of resource management under special conditions is put forward to optimize the performance of ISTX2.0.The thesis finally compares the resource management of ISTX1.0 and ISTX2.0 in seven aspects, including the way of applications accessing databases, connection, connection pooling, supporting for transactions transfer in different threads, the way of resource management components accessing databases, management of resource managers, suitable environments to be used, and specifications followed. It also summarizes the contents of the paper, and puts forward the following work.