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Qu, Huiming (2008) MANAGING QUERY AND UPDATE TRANSACTIONS UNDER QUALITY CONTRACTS IN WEB-DATABASES. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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In modern Web-database systems, users typically perform read-only queries, whereas all write-only data updates are performed in the background, concurrently with queries.For most of these services to be successful and their users to be kept satisfied, two criteria need to be met: user requests must be answered in a timely fashion and must return fresh data. This is relatively easy when the system is lightly loaded and, as such, both queries and updates can be executed quickly. However, this goal becomes practically hard to achieve in real systems due to the high volumes of queries and updates, especially in periods of flash crowds. In this work, we argue it is beneficial to allow users to specify their preferences and let the system optimize towards satisfying user preferences, instead of simply improving the average case. We believe that this user-centric approach will empower the system to gracefully deal with a broader spectrum of workloads.Towards user-centric web-databases, we propose a Quality Contracts framework to help users express their preferences over multiple quality specifications. Moreover, we propose a suite of algorithms to effectively perform load balancing and scheduling for both queries and updates according to user preferences. We evaluate the proposed framework and algorithms through a simulation with real traces from disk accesses and from a stock information website. Finally, to increase the applicability of Quality Contracts enhanced Web-database systems, we propose an algorithm to help users adapt to the Web-database system behavior and maximize their query success ratio.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Qu, Huiminghuiming@cs.pitt.eduHUQ2
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairLabrinidis, Alexandroslabrinid@cs.pitt.eduLABRINID
Committee MemberMosse, Danielmosse@cs.pitt.eduMOSSE
Committee MemberXiong,
Committee MemberChrysanthis, Panos Kpanos@cs.pitt.eduPANOS
Date: 29 January 2008
Date Type: Completion
Defense Date: 31 August 2007
Approval Date: 29 January 2008
Submission Date: 29 November 2007
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Institution: University of Pittsburgh
Schools and Programs: Dietrich School of Arts and Sciences > Computer Science
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: scheduling; transaction management; admission control; quality contracts; web-databases
Other ID:, etd-11292007-134700
Date Deposited: 10 Nov 2011 20:06
Last Modified: 19 Dec 2016 14:37


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