T*-tree: a main memory database index structure for real time applications

Abstract

In this paper, we propose an indexing structure, called T*-tree, for efficient processing of real time applications under main memory database management systems (MMDBMS). T*-tree is an index structure for rapid data access and saves memory space under MMDBMS. T-tree is well known to be one of the best index structures for ordered data in MMDB. Existing T-tree is a balanced tree that evolved from AVL and B-trees, and a binary tree with many elements in a node. T-tree retains the intrinsic binary search nature, and is also good in memory use. However T-tree has major disadvantage; the tree traversal for range queries and the movement of overflow/underflow data due to data insertion/deletion on internal nodes. We propose T*-tree as a alternative structure, which is an improvement from T-tree for better use of query operations, including range queries and which contains all other good features of T-tree. We also show the pseudo-algorithms of search, update, delete, and rebalancing operations for T*-tree, with performance test results. The results indicate that T*-tree provides better performance for range queries compared to T-tree.