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2007
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Collecting and Maintaining Just-in-Time Statistics

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Collecting and Maintaining Just-in-Time Statistics
Traditional DBMSs decouple statistics collection and query optimization both in space and time. Decoupling in time may lead to outdated statistics. Decoupling in space may cause statistics not to be available at the desired granularity needed to optimize a particular query, or some important statistics may not be available at all. Overall, this decoupling often leads to large cardinality estimation errors and, in consequence, to the selection of suboptimal plans for query execution. In this paper, we present JITS, a system for proactively collecting query-specific statistics during query compilation. The system employs a lightweight sensitivity analysis to choose which statistics to collect by making use of previously collected statistics and database activity patterns. The collected statistics are materialized and incrementally updated for later reuse. We present the basic concepts, architecture, and key features of JITS. We demonstrate its benefits through an extensive experimental ...
Amr El-Helw, Ihab F. Ilyas, Wing Lau, Volker Markl
Added 01 Nov 2009
Updated 01 Nov 2009
Type Conference
Year 2007
Where ICDE
Authors Amr El-Helw, Ihab F. Ilyas, Wing Lau, Volker Markl, Calisto Zuzarte
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