Kang Eun Ho , Yun Seog U , Kim Gyeong Chang

The KIPS Transactions:PartD, Vol. 11, No. 1, pp. 11-22, Feb. 2004
10.3745/KIPSTD.2004.11.1.11,   PDF Download:

Abstract

As Random access memory chip gets cheaper, it becomes affordable to realize main memory-based database systems. Consequently, reducing cache misses emerges as the most important issue in current main memory databases, in which CPU speeds have been increasing at 60% per year, compared to the memory speeds at 10% per year. In this paper, we design and implement a main-memory database system for real-time mobile GIS. Our system is composed of 5 modules : the interface manager provides the interface for PDA users ; the memory data manager controls spatial and non-spatial data in main-memory using virtual memory techniques ; the query manager processes spatial and non-spatial query ; the index manager manages the MR-tree index for spatial data and the T-tree index for non-spatial index ; the GIS server interface provides the interface with disk-based GIS. The MR-tree propsed propagates node splits upward only if one of the internal nodes on the insertion path has empty space. Thus, the internal nodes of the MR-tree are almost 100% full. Our experimental study shows that the two-dimential MR-tree performs search up to 2.4 times faster than the ordinary R-tree. To use virtual memeory techniques, the memory data manager uses page tables for spatial data, non-spatial data, T-tree and MR-tree. And, it uses indirect addressing techniques for fast reloading from disk.

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