Preference structures and their numerical representations
Theoretical Computer Science
The EVE Approach: View Synchronization in Dynamic Distributed Environments
IEEE Transactions on Knowledge and Data Engineering
An XML query engine for network-bound data
The VLDB Journal — The International Journal on Very Large Data Bases
Approximate join processing over data streams
Proceedings of the 2003 ACM SIGMOD international conference on Management of data
Stream processing of XPath queries with predicates
Proceedings of the 2003 ACM SIGMOD international conference on Management of data
XPath queries on streaming data
Proceedings of the 2003 ACM SIGMOD international conference on Management of data
Raindrop: a uniform and layered algebraic framework for XQueries on XML streams
CIKM '03 Proceedings of the twelfth international conference on Information and knowledge management
Load Shedding for Aggregation Queries over Data Streams
ICDE '04 Proceedings of the 20th International Conference on Data Engineering
Static optimization of conjunctive queries with sliding windows over infinite streams
SIGMOD '04 Proceedings of the 2004 ACM SIGMOD international conference on Management of data
Semantic caching for xml queries
Semantic caching for xml queries
Adaptive load shedding for windowed stream joins
Proceedings of the 14th ACM international conference on Information and knowledge management
Window-aware load shedding for aggregation queries over data streams
VLDB '06 Proceedings of the 32nd international conference on Very large data bases
A transducer-based XML query processor
VLDB '02 Proceedings of the 28th international conference on Very Large Data Bases
Preference SQL: design, implementation, experiences
VLDB '02 Proceedings of the 28th international conference on Very Large Data Bases
Query processing for high-volume XML message brokering
VLDB '03 Proceedings of the 29th international conference on Very large data bases - Volume 29
Memory-limited execution of windowed stream joins
VLDB '04 Proceedings of the Thirtieth international conference on Very large data bases - Volume 30
FluXQuery: an optimizing XQuery processor for streaming XML data
VLDB '04 Proceedings of the Thirtieth international conference on Very large data bases - Volume 30
Automaton in or out: run-time plan optimization for XML stream processing
SSPS '08 Proceedings of the 2nd international workshop on Scalable stream processing system
Synopsis based load shedding in XML streams
Proceedings of the 2009 EDBT/ICDT Workshops
Proceedings of the VLDB Endowment
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Because of the high volume and unpredictable arrival rate, stream processing systems may not always be able to keep up with the input data streams - resulting in buffer overflow and uncontrolled loss of data. Load shedding, the prevalent strategy for solving this overflow problem, has so far only been considered for relational stream processing, but not for XML. Shedding applied to XML stream processing brings new opportunities and challenges due to complex nested nature of XML structures. In this paper, we tackle this unsolved XML shedding problem using a three-pronged approach. First, we develop an XQuery preference model that enables users to specify the relative importance of preserving different subpatterns in the XML result structure. This transforms shedding into the problem of rewriting the user query into shed queries that return approximate query answers with utility as measured by the given user preference model. Second, we develop a cost model to compare the performance of alternate shed queries. Third, we develop two shedding algorithms, OptShed and FastShed. OptShed guarantees to find an optimal solution however at the cost of exponential complexity. FastShed, as confirmed by our experiments, achieves a close-to-optimal result in a wide range of test cases. Finally we describe the in-automaton shedding mechanism for XQuery stream engines. The experiments show that our proposed utility-driven shedding solutions consistently achieve higher utility results compared to the existing relational shedding techniques.