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Frontiers of Computer Science

Front. Comput. Sci.    2018, Vol. 12 Issue (1) : 146-162
Handling query skew in large indexes: a view based approach
Weihuang HUANG(), Jeffrey Xu YU, Zechao SHANG
Systems Engineering and EngineeringManagement, The Chinese University of Hong Kong, Hong Kong, China
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Indexing is one of the most important techniques to facilitate query processing over a multi-dimensional dataset. A commonly used strategy for such indexing is to keep the tree-structured index balanced. This strategy reduces query processing cost in the worst case, and can handle all different queries equally well. In other words, this strategy implies that all queries are uniformly issued, which is partially because the query distribution is not possibly known and will change over time in practice. A key issue we study in this work is whether it is the best to fully rely on a balanced tree-structured index in particular when datasets become larger and larger in the big data era. This means that, when a dataset becomes very large, it becomes unreasonable to assume that all data in any subspace are equally important and are uniformly accessed by all queries at the index level. Given the existence of query skew and the possible changes of query skew, in this paper, we study how to handle such query skew and such query skew changes at the index level without sacrifice of supporting any possible queries in a wellbalanced tree index and without a high overhead. To tackle the issue, we propose index-view at the index level, where an index-view is a short-cut in a balanced tree-structured index to access objects in the subspaces that are more frequently accessed, and propose a new index-view-centric framework for query processing using index-views in a bottom-up manner. We study index-views selection problem in both static and dynamic setting, and we confirm the effectiveness of our approach using large real and synthetic datasets.

Keywords multi-dimensional index      query adaptive      indexview     
Corresponding Authors: Weihuang HUANG   
Just Accepted Date: 18 July 2016   Online First Date: 22 September 2017    Issue Date: 12 January 2018
 Cite this article:   
Weihuang HUANG,Jeffrey Xu YU,Zechao SHANG. Handling query skew in large indexes: a view based approach[J]. Front. Comput. Sci., 2018, 12(1): 146-162.
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Weihuang HUANG
Jeffrey Xu YU
Zechao SHANG
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