Join Algorithms Based on Tertiary Storage
基于三级存储器的Join算法

The Join algorithms of massive relations in relational databases based on tertiary storage are studied in this paper. At present, Hash-Based Join algorithms are the best ones. However, the effect of tape locate time is not taken into consideration in these algorithms. It has great influence on the time complexity of the Join algorithms to locate positions on tertiary storages. For this reason, two new Join algorithms of massive relations in relational databases are proposed based on tertiary storage, Disk-Based-Hash-Join algorithm and Tertiary-Only-Hash-Join algorithm. Adopting disk buffer technique and the method of storing hashed data concentratedly, the cost of the random position locating on tertiary storage is much lower than other algorithms so that the proposed Join algorithms are more efficient. The analysis and experimental results show that the performance of this algorithms is superior to others, and thus they are suitable for massive database management.