| Firstly, this paper introduces the background, evolution and present of 00DB. By comparing the fundamental features, development modes, applicable fields and performance with those of traditional RDB, it indicates that 00DB is more suitable in modern industrial fields which need plentiful data types and complicate data relationships. Secondly, this paper briefly describes the design and implementation of our proposed OODBMS prototype-TR-OODB, which is based on ODMG standards and the non-fixed record storing mechanism SSM( Short Storage Manager ) designed by University of Wisconsin-madison. TR-OODB uses Client/Server architecture and uses CORBA as its communication mode. This kind of implement on makes communication between clients and server could only be performed at object level and server transactions have to be mapped one by one with their user-mode threads. These overheads significantly slow down the overall performance of the whole system. By summarizing the experience obtained during the development of TR-OODB, this paper proposes a new OODBMS-ONet. In order to break the performance bottle-neck, the ONet server side follows two vital design: 1) C/S architecture is based on page server mode, which enables page as the transmission unit between clients and server; 2) uses passive transaction mode, which separates database transactions from executable units of the operating system, such as threads. In addition, because of the effective design of storage management layer in ONet server side, it perfectly implements multi-threading mechanism using I/O completion ports & thread pooling techniques provided by Windows NT/2000. As key points of this paper, it describes in detail about design principles, solutions and related implementations of the storage management in ONet server side. Some important technical issues on the implementation of ONet client and the perspective of the system are discussed at last section of this paper. |
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