Histogram-Aware Sorting for Enhanced Word-Aligned Compression in Bitmap Indexes [r-libre/223]

Kaser, Owen; Lemire, Daniel et Aouiche, Kamel (2008). Histogram-Aware Sorting for Enhanced Word-Aligned Compression in Bitmap Indexes. Dans Proceedings of the 11th ACM International Workshop on Data Warehousing and OLAP. ACM.

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Catégorie de document :	Communications dans des actes de congrès/colloques
Évaluation par un comité de lecture :	Oui
Étape de publication :	Publié
Résumé :	Bitmap indexes must be compressed to reduce input/output costs and minimize CPU usage. To accelerate logical operations (AND, OR, XOR) over bitmaps, we use techniques based on run-length encoding (RLE), such as Word-Aligned Hybrid (WAH) compression. These techniques are sensitive to the order of the rows: a simple lexicographical sort can divide the index size by 9 and make indexes several times faster. We investigate reordering heuristics based on computed attribute-value histograms. Simply permuting the columns of the table based on these histograms can increase the sorting efficiency by 40%.
Déposant:	Lemire, Daniel
Responsable :	Daniel Lemire
Dépôt :	22 juill. 2014 21:48
Dernière modification :	16 juill. 2015 00:47

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