SIGMOD '89 Proceedings of the 1989 ACM SIGMOD international conference on Management of data
Tradeoffs in processing complex join queries via hashing in multiprocessor database machines
Proceedings of the sixteenth international conference on Very large databases
A performance evaluation of pointer-based joins
SIGMOD '90 Proceedings of the 1990 ACM SIGMOD international conference on Management of data
Parallel evaluation of multi-join queries
SIGMOD '95 Proceedings of the 1995 ACM SIGMOD international conference on Management of data
A cost model for path expressions in object-oriented queries
Journal of Database Management
The object database standard: ODMG 2.0
The object database standard: ODMG 2.0
Parallel query processing in DBS3
PDIS '93 Proceedings of the second international conference on Parallel and distributed information systems
Parallel pointer-based join techniques for object-oriented database
PDIS '93 Proceedings of the second international conference on Parallel and distributed information systems
Parallel query processing with zigzag trees
The VLDB Journal — The International Journal on Very Large Data Bases - Parallelism in database systems
Algorithms for Asynchronous Parallel Processing of Object-Oriented Databases
IEEE Transactions on Knowledge and Data Engineering
Applying Segmented Right-Deep Trees to Pipelining Multiple Hash Joins
IEEE Transactions on Knowledge and Data Engineering
Parallelism in Object-Oriented Query Processing
Proceedings of the Sixth International Conference on Data Engineering
ICDE '96 Proceedings of the Twelfth International Conference on Data Engineering
Using Segmented Right-Deep Trees for the Execution of Pipelined Hash Joins
VLDB '92 Proceedings of the 18th International Conference on Very Large Data Bases
On the Effectiveness of Optimization Search Strategies for Parallel Execution Spaces
VLDB '93 Proceedings of the 19th International Conference on Very Large Data Bases
Cost-based Selection of Path Expression Processing Algorithms in Object-Oriented Databases
VLDB '96 Proceedings of the 22th International Conference on Very Large Data Bases
Query Optimization Techniques Utilizing Path Indexes in Object-Oriented Database Systems
Proceedings of the Fifth International Conference on Database Systems for Advanced Applications (DASFAA)
A Heuristic Approach for Optimization of Path Expressions
DEXA '95 Proceedings of the 6th International Conference on Database and Expert Systems Applications
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With the emerging of new applications, especially in Web, such as E-Commerce, Digital Library and DNA Bank, object database systems show their stronger functions than other kinds of database systems due to their powerful representation ability on complex semantics and relationship. One distinguished feature of object database systems is path expression, and most queries on an object database are based on path expression because it is the most natural and convenient way to access the object database, for example, to navigate the hyperlinks in a web-based database. The execution of path expression is usually extremely expensive on a very large database. Therefore, the improvement of path expression execution efficiency is critical for the performance of object databases. As an important approach realizing high-performance query processing, the parallel processing of path expression on distributed object databases is explored in this paper. Up to now, some algorithms about how to compute path expressions and how to optimize path expression processing have been proposed for centralized environments. But, few approaches have been presented for computing path expressions in parallel. In this paper, a new parallel algorithm for computing path expression named Parallel Cascade Semijoin (PCSJ) is proposed. Moreover, a new scheduling strategy called right-deep zigzag tree is designed to further improve the performance of the PCSJ algorithm. The experiments have been implemented in an NOW distributed and parallel environment. The results show that the PCSJ algorithm outperforms the other two parallel algorithms (the parallel version of forward pointer chasing algorithm (PFPC) and the index splitting parallel algorithm (IndexSplit)) when computing path expressions with restrictive predicates and that the right-deep zigzag tree scheduling strategy has better performance than the right-deep tree scheduling strategy.