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2010
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Position list word aligned hybrid: optimizing space and performance for compressed bitmaps

11 years 6 months ago
Position list word aligned hybrid: optimizing space and performance for compressed bitmaps
Compressed bitmap indexes are increasingly used for efficiently querying very large and complex databases. The Word Aligned Hybrid (WAH) bitmap compression scheme is commonly recognized as the most efficient compression scheme in terms of CPU efficiency. However, WAH compressed bitmaps use a lot of storage space. This paper presents the Position List Word Aligned Hybrid (PLWAH) compression scheme that improves significantly over WAH compression by better utilizing the available bits and new CPU instructions. For typical bit distributions, PLWAH compressed bitmaps are often half the size of WAH bitmaps and, at the same time, offer an even better CPU efficiency. The results are verified by theoretical estimates and extensive experiments on large amounts of both synthetic and real-world data.
François Deliège, Torben Bach Peders
Added 28 May 2010
Updated 28 May 2010
Type Conference
Year 2010
Where EDBT
Authors François Deliège, Torben Bach Pedersen
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