Vertically-partitioned parallel signature file method

Recently, parallel signature file methods have been proposed for better retrieval performance in signature files. In this paper, we propose a vertically-partitioned parallel signature file (VPSF) method which can partition a signature file vertically. Our VPSF method uses an extendable hashing technique for dynamic environment and uses a frame-sliced signature file technique for efficient retrieval. Our VPSF method also can eliminate the data skew and the execution skew by allocating each frame to a processing node. To prove the efficiency of our VPSF method, we compare its performance with those of the conventional parallel signature file methods, i.e., HPSF and Hamming filter, in terms of retrieval time, storage overhead, and insertion time. The experimental result shows that our VPSF achieves about 40% better retrieval performance than the Hamming filter. In addition, we evaluate the performance of our VPSF methods on several normal distributions with half and double standard deviations of the real data. From the performance evaluation on record sets with half standard deviation, we show that our VPSF gains about 20¯50% improvement in retrieval time, compared with the Hamming filter and the HPSF. Finally, we show that our VPSF generally outperforms the conventional parallel signature files on retrieval performance when the records of a database are uniform in size.