Abstract
With the rapid increasing capacity of flash memory, flash-aware indexing techniques are highly desirable for flash devices. The unique features of flash memory, such as the erase-before-write constraint and the asymmetric read/write cost, severely deteriorate the performance of the traditional B+-tree algorithm. In this paper, we propose an optimized indexing method, called lazy-update B+-tree, to overcome the limitations of flash memory. The basic idea is to defer the committing of update requests to the B+-tree by buffering them in a segment of main memory. They are later committed in groups so that the cost of each write operation can be amortized by a bunch of update requests. We identify a victim selection problem for the lazy-update B+-tree and develop two heuristic-based commit policies to address this problem. Simulation results show that the proposed lazy-update method, along with a well-designed commit policy, greatly improves the update performance of the traditional B+-tree while preserving the query efficiency.
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This work is supported by the Research Grants Council of Hong Kong under Grant No. HKBU210808 and the National Natural Science Foundation of China under Grant No. 60833005.
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Tung On, S., Hu, H., Li, Y. et al. Flash-Optimized B+-Tree. J. Comput. Sci. Technol. 25, 509–522 (2010). https://doi.org/10.1007/s11390-010-9341-1
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DOI: https://doi.org/10.1007/s11390-010-9341-1