Efficient Distribution of Full-Fledged XQuery

Zhang, Ying; Tang, Nan; Boncz, Peter

doi:10.1109/icde.2009.79

Cited by 7 publications

(8 citation statements)

References 20 publications

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“…Other works, e.g., [6], [8], [32] only focus on a restricted subset of XQUERY queries. This paper is based on our previous work on decomposing read-only XQuery queries [40]. As one of the main goals of our work is to support fullfledged XQuery, in this paper, we have made our framework more complete by extending [40] with analysis on how updating queries can be decomposed.…”

Section: Related Workmentioning

confidence: 97%

Projective Distribution of XQuery with Updates

Zhang

Tang

Boncz

2010

IEEE Trans. Knowl. Data Eng.

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We investigate techniques to automatically decompose any XQuery query-including updating queries specified by the XQuery Update Facility (XQUF)-into subqueries, that can be executed near their data sources, i.e., function-shipping. The main challenge addressed here is to ensure that the decomposed queries properly respect XML node identity and preserve structural properties, when (parts of) XML nodes are sent over the network, effectively copying them. We start by precisely characterizing the conditions, under which pass-by-value parameter passing causes semantic differences between remote execution of an XQuery expression and its local execution. We then formulate a conservative strategy that effectively avoids decomposition in such cases. To broaden the possibilities of query distribution, we extend the pass-by-value semantics to a pass-by-fragment semantics, which keeps better track of node identities and structural properties. The pass-by-fragment semantics is subsequently refined to a pass-byprojection semantics by means of a novel runtime XML projection technique, which safely eliminates most semantic differences between the local and remote execution of an XQuery expression, and strongly reduces message sizes. Finally, we discuss how these techniques can be used for updating queries, both under the standard W3C XQUF specification, as well as under an extended semantics that allows to update remote documents. The proposed techniques are implemented in XRPC, a simple yet efficient XQuery extension that enables function-shipping by adding a Remote Procedure Call mechanism to XQuery. Experiments on MonetDB/ XQuery establish the performance potential of our XQuery decomposition techniques.

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Section: Related Workmentioning

confidence: 97%

Projective Distribution of XQuery with Updates

Zhang

Tang

Boncz

2010

IEEE Trans. Knowl. Data Eng.

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“…Based on the XRPC extension of XQuery, Zhang et al describe a technique that transforms a centralized, data shipping-oriented query into a distributed, query shipping equivalent [44]. This is achieved by decomposing the query and pushing part of the query execution to remote sites.…”

Section: Query Decompositionmentioning

confidence: 98%

Scaling XML query processing: distribution, localization and pruning

Kling

Özsu

Daudjee

2011

Distrib Parallel Databases

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Distributing data collections by fragmenting them is an effective way of improving the scalability of a database system. While the distribution of relational data is well understood, the unique characteristics of the XML data and query model present challenges that require different distribution techniques. In this paper, we show how XML data can be fragmented horizontally and vertically. Based on this, we propose solutions to two of the problems encountered in distributed query processing and optimization on XML data, namely localization and pruning. Localization takes a fragmentation-unaware query plan and converts it to a distributed query plan that can be executed at the sites that hold XML data fragments in a distributed system. We then show how the resulting distributed query plan can be pruned so that only those sites are accessed that can contribute to the query result. We demonstrate that our techniques can be integrated into a real-life XML database system and that they significantly improve the performance of distributed query execution.

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“…However we just use a pure distributed XQuery query without referring other information. [12,13] proposes some methods for the efficient processing of distributed streaming XML data. Their approaches include a method for generating a local query.…”

Section: Related Workmentioning

confidence: 99%

“…We adopt a subset of XQuery Core expression. like [12]. Table 1 XPath expressions in distributed queries address nodes which are used to process the distributed queries among nodes stored in local systems.…”

Section: B Local Query Generationmentioning

confidence: 99%

Local Query Generation for Distributed XQuery Queries

Park

Kang

2010

2010 International Conference on Cyber-Enabled Distributed Computing and Knowledge Discovery

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XML view is proposed to integrate between XML data and heterogeneous data over distributed environment and global XML view is used to search distributed heterogeneous data. Distributed XQuery queries based on a global XML view can search heterogeneous data seamlessly, being distributed in the local systems. One of the basic and simple methods to process distributed SQL queries is that generates local SQL queries for processing a distributed SQL query and constructs the result of the distributed query from the results of the local queries. Therefore, it is natural to consider how the method for distributed SQL queries can be applied to processing XQuery queries. However, the syntax of XQuery differs from SQL because the XQuery contains some special expressions like FOR clauses for querying to semi-structured data. Therefore, this paper defines some problems to generate local XQuery queries for processing distributed XQuery queries and proposes a method for generating local XQuery queries considered these problems. We also implement a distributed XQuery query processor using our method.

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Efficient Distribution of Full-Fledged XQuery

Cited by 7 publications

References 20 publications

Projective Distribution of XQuery with Updates

Projective Distribution of XQuery with Updates

Scaling XML query processing: distribution, localization and pruning

Local Query Generation for Distributed XQuery Queries

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