Q-Cop

Avoiding bad query mixes to minimize client timeouts under heavy loads

Sean Tozer, Tim Brecht, Ashraf Aboulnaga

Research output: Chapter in Book/Report/Conference proceedingConference contribution

31 Citations (Scopus)

Abstract

In three-tiered web applications, some form of admission control is required to ensure that throughput and response times are not significantly harmed during periods of heavy load. We propose Q-Cop, a prototype system for improving admission control decisions that considers a combination of the load on the system, the number of simultaneous queries being executed, the actual mix of queries being executed, and the expected time a user may wait for a reply before they or their browser give up (i.e., time out). Using TPC-W queries, we show that the response times of different types of queries can vary significantly depending not just on the number of queries being processed but on the mix of other queries that are running simultaneously. We develop a model of expected query execution times that accounts for the mix of queries being executed and integrate this model into a three-tiered system to make admission control decisions. Our results show that this approach makes more informed decisions about which queries to reject and as a result significantly reduces the number of requests that time out. Across the range of workloads examined an average of 47% fewer requests are unsuccessful than the next best approach.

Original languageEnglish
Title of host publicationProceedings - International Conference on Data Engineering
Pages397-408
Number of pages12
DOIs
Publication statusPublished - 1 Jun 2010
Externally publishedYes
Event26th IEEE International Conference on Data Engineering, ICDE 2010 - Long Beach, CA, United States
Duration: 1 Mar 20106 Mar 2010

Other

Other26th IEEE International Conference on Data Engineering, ICDE 2010
CountryUnited States
CityLong Beach, CA
Period1/3/106/3/10

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ASJC Scopus subject areas

  • Information Systems
  • Signal Processing
  • Software

Cite this

Tozer, S., Brecht, T., & Aboulnaga, A. (2010). Q-Cop: Avoiding bad query mixes to minimize client timeouts under heavy loads. In Proceedings - International Conference on Data Engineering (pp. 397-408). [5447850] https://doi.org/10.1109/ICDE.2010.5447850

Q-Cop : Avoiding bad query mixes to minimize client timeouts under heavy loads. / Tozer, Sean; Brecht, Tim; Aboulnaga, Ashraf.

Proceedings - International Conference on Data Engineering. 2010. p. 397-408 5447850.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Tozer, S, Brecht, T & Aboulnaga, A 2010, Q-Cop: Avoiding bad query mixes to minimize client timeouts under heavy loads. in Proceedings - International Conference on Data Engineering., 5447850, pp. 397-408, 26th IEEE International Conference on Data Engineering, ICDE 2010, Long Beach, CA, United States, 1/3/10. https://doi.org/10.1109/ICDE.2010.5447850
Tozer S, Brecht T, Aboulnaga A. Q-Cop: Avoiding bad query mixes to minimize client timeouts under heavy loads. In Proceedings - International Conference on Data Engineering. 2010. p. 397-408. 5447850 https://doi.org/10.1109/ICDE.2010.5447850
Tozer, Sean ; Brecht, Tim ; Aboulnaga, Ashraf. / Q-Cop : Avoiding bad query mixes to minimize client timeouts under heavy loads. Proceedings - International Conference on Data Engineering. 2010. pp. 397-408
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