Results 1 - 10
of
30
XRPC: Interoperable and Efficient Distributed XQuery
- In VLDB
, 2007
"... We propose XRPC, a minimal XQuery extension that enables distributed yet efficient querying of heterogeneous XQuery data sources. XRPC enhances the existing concept of XQuery functions with the Remote Procedure Call (RPC) paradigm. By calling out of an XQueryfor-loop to multiple destinations, and by ..."
Abstract
-
Cited by 24 (5 self)
- Add to MetaCart
(Show Context)
We propose XRPC, a minimal XQuery extension that enables distributed yet efficient querying of heterogeneous XQuery data sources. XRPC enhances the existing concept of XQuery functions with the Remote Procedure Call (RPC) paradigm. By calling out of an XQueryfor-loop to multiple destinations, and by calling functions that themselves perform XRPC calls, complex P2P communication patterns can be achieved. The XRPC extension is orthogonal to all XQuery features, including the XQuery Update Facility (XQUF). We provide formal semantics for XRPC that encompasses execution of both read-only and update queries. XRPC is also a network SOAP sub-protocol, that integrates seamlessly with web services and Service Oriented Architectures (SOA), and AJAX-based GUIs. A crucial feature of the protocol is bulk RPC, that allows remote execution of many different calls to the same procedure, using possibly a single network round-trip. The efficiency potential of XRPC is demonstrated via an open-source implementation in MonetDB/XQuery. We show, however, that XRPC is not system-specific: every XQuery data source can service XRPC calls using a wrapper. Since XQuery is a pure functional language, we can leverage techniques developed for functional query decomposition to rewrite data shipping queries into XRPC-based function shipping queries. Powerful distributed database techniques (such as semi-join optimizations) directly map on bulk RPC, opening up interesting future work opportunities. 1.
Efficient maintenance techniques for views over active documents
- In International Conference on Extending Database Technology (EDBT
, 2009
"... Many Web applications are based on dynamic interactions between Web components exchanging flows of information. Such a situation arises for instance in mashup systems or when monitoring distributed autonomous systems. Our work is in this challenging context that has generated recently a lot of atten ..."
Abstract
-
Cited by 14 (4 self)
- Add to MetaCart
(Show Context)
Many Web applications are based on dynamic interactions between Web components exchanging flows of information. Such a situation arises for instance in mashup systems or when monitoring distributed autonomous systems. Our work is in this challenging context that has generated recently a lot of attention; see Web 2.0. We introduce the axlog formal model for capturing such interactions and show how this model can be supported efficiently. The central component is the axlog widget defined by one tree-pattern query or more, over an active document (in the Active XML style) that includes some input streams of updates. A widget generates a stream of updates for each query, the updates that are needed to maintain the view corresponding to the query. We exploit an array of known technologies: datalog optimization techniques such as Differential or MagicSet, constraint query languages, and efficient XML filtering (YFilter). The novel optimization technique we propose is based on fundamental new notions: a relevance (different than that of MagicSet), satisfiability and provenance for active documents. We briefly discuss an implementation of an axlog engine, an application that we used to test the approach, and results of experiments. 1.
Distributed Monitoring of Peer to Peer Systems (demonstration
- in "International Conference on Data Engineering
, 2008
"... In this paper, we are concerned with the distributed monitoring of P2P systems. We introduce the P2P Monitor system and a new declarative language, namely P2PML, for specifying monitoring tasks. A P2PML subscription is compiled into a distributed algebraic plan which is described using algebra over ..."
Abstract
-
Cited by 11 (6 self)
- Add to MetaCart
(Show Context)
In this paper, we are concerned with the distributed monitoring of P2P systems. We introduce the P2P Monitor system and a new declarative language, namely P2PML, for specifying monitoring tasks. A P2PML subscription is compiled into a distributed algebraic plan which is described using algebra over XML streams. The operators of this algebra are first alerters in charge of detecting specific events and acting as stream sources. Other operators process the streams or publish them. We introduce a filter for streams of XML documents that scales by processing first simple conditions and then, if still needed, evaluating complex queries. We also show how particular tasks can be supported by identifying subtasks that are already provided by existing streams.
The Data Ring: Community Content Sharing
- In Third Biennial Conference on Innovative Data Systems Research (CIDR 2007), Asilomar
, 2007
"... Information ubiquity has created a large crowd of users ..."
Abstract
-
Cited by 8 (5 self)
- Add to MetaCart
(Show Context)
Information ubiquity has created a large crowd of users
Distributed XML design
, 2009
"... A distributed XML document is an XML document that spans several machines or Web repositories. We assume that a distribution design of the document tree is given, providing an XML tree some of whose leaves are “docking points”, to which XML subtrees can be attached. These subtrees may be provided an ..."
Abstract
-
Cited by 8 (0 self)
- Add to MetaCart
A distributed XML document is an XML document that spans several machines or Web repositories. We assume that a distribution design of the document tree is given, providing an XML tree some of whose leaves are “docking points”, to which XML subtrees can be attached. These subtrees may be provided and controlled by peers at remote locations, or may correspond to the result of function calls, e.g., Web services. If a global type τ, e.g. a DTD, is specified for a distributed document T, it would be most desirable to be able to break this type into a collection of local types, called a local typing, such that the document satisfies τ if and only if each peer (or function) satisfies its local type. In this paper we lay out the fundamentals of a theory of local typing and provide formal definitions of three main variants of locality: local typing, maximal local typing, and perfect typing, the latter being the most desirable. We study the following relevant decision problems: (i) given a typing for a design, determine whether it is local, maximal local, or perfect; (ii) given a design, establish whether a (maximal) local, or perfect typing does exist. For some of these problems we provide tight complexity bounds (polynomial space), while for the others we show exponential upper bounds. A main contribution is a polynomial-space algorithm for computing a perfect typing in this context, if it exists.
OptimAX: Optimizing Distributed ActiveXML Applications
- In ICWE
, 2008
"... The Web has become a platform of choice for the deployment of complex applications involving several business partners. Typically, such applications interoperate by means of Web services, exchanging XML information. We present OptimAX, an optimization Web service that applies at the static level (pr ..."
Abstract
-
Cited by 6 (1 self)
- Add to MetaCart
(Show Context)
The Web has become a platform of choice for the deployment of complex applications involving several business partners. Typically, such applications interoperate by means of Web services, exchanging XML information. We present OptimAX, an optimization Web service that applies at the static level (prior to enacting an application) in order to rewrite it into one whose execution will be more performant. OptimAX builds on the ActiveXML (AXML) data-centric Web service composition language, and demonstrates how database-style techniques can be efficiently integrated in a loosely-coupled, distributed application based on Web services. OptimAX has been fully implemented and we describe its experimental performance. Figure 1. WebContent architecture outline. 1
WebContent: Efficient P2P Warehousing of Web Data
, 2008
"... We present the WebContent platform for managing distributed repositories of XML and semantic Web data. The platform allows integrating various data processing building blocks (crawling, translation, semantic annotation, full-text search, structured XML querying, and semantic querying), presented as ..."
Abstract
-
Cited by 6 (2 self)
- Add to MetaCart
We present the WebContent platform for managing distributed repositories of XML and semantic Web data. The platform allows integrating various data processing building blocks (crawling, translation, semantic annotation, full-text search, structured XML querying, and semantic querying), presented as Web services, into a large-scale efficient platform. Calls to various services are combined inside ActiveXML [8] documents, which are XML documents including service calls. An ActiveXML optimizer is used to: (i) efficiently distribute computations among sites; (ii) perform XQuery-specific optimizations by leveraging an algebraic XQuery optimizer; and (iii) given an XML query, chose among several distributed indices the most appropriate in order to answer the query.
On the Equivalence of Distributed Systems with Queries and Communication
- INTERNATIONAL CONFERENCE ON DATABASE THEORY
, 2011
"... Distributed data management systems consist of peers that store, exchange and process data in order to collaboratively achieve a common goal, such as evaluate some query. We study the equivalence of such systems. We model a distributed system by a collection of Active XML documents, i.e., trees augm ..."
Abstract
-
Cited by 5 (2 self)
- Add to MetaCart
(Show Context)
Distributed data management systems consist of peers that store, exchange and process data in order to collaboratively achieve a common goal, such as evaluate some query. We study the equivalence of such systems. We model a distributed system by a collection of Active XML documents, i.e., trees augmented with function calls for performing tasks such as sending, receiving and querying data. As our model is quite general, the equivalence problem turns out to be undecidable. However, we exhibit several restrictions of the model, for which equivalence can be effectively decided. We also study the computational complexity of the equivalence problem, and present an axiomatization of equivalence, in the form of a set of equivalence-preserving rewrite rules allowing us to optimize a system by rewriting it into an equivalent, but possibly more efficient system.
XCraft: A Dynamic Optimizer for the Materialization of Active XML Documents. 2006, COPPE/UFRJ: Rio de Janeiro.Technical Report ES-709/07
"... An active XML (AXML) document contains special tags that represent calls to Web services. Retrieving its contents consists in materializing its data elements by invoking all its embedded service calls in a P2P network. In this process, the results of some service calls are often used as inputs to ot ..."
Abstract
-
Cited by 4 (4 self)
- Add to MetaCart
(Show Context)
An active XML (AXML) document contains special tags that represent calls to Web services. Retrieving its contents consists in materializing its data elements by invoking all its embedded service calls in a P2P network. In this process, the results of some service calls are often used as inputs to other calls. Also, usually several peers provide each requested Web service, and peers can collaborate to invoke these services. This implies many equivalent materialization alternatives, with different performance. Optimizing the AXML materialization process is a hard problem, which often involves searching a huge space of solutions. Current techniques for workflow scheduling and distributed query processing are insufficient for this problem, since in AXML materialization: (i) the set of participating
OptimAX: Efficient Support for Data-Intensive Mash-Ups (demo
- In ICDE
, 2008
"... Abstract — Mash-ups are being used in various Web-based applications of Web 2.0 which combine instantly information from different sources. Active XML (AXML, in short) language is a tool for decentralized, data-centric Web service integration. AXML document includes calls to services that may be eit ..."
Abstract
-
Cited by 4 (2 self)
- Add to MetaCart
(Show Context)
Abstract — Mash-ups are being used in various Web-based applications of Web 2.0 which combine instantly information from different sources. Active XML (AXML, in short) language is a tool for decentralized, data-centric Web service integration. AXML document includes calls to services that may be either simple request-responses either long running subscriptions. Being fully composable and allowing resource sharing makes AXML ideal for mash-up style integration. In this demo we present how AXML can be used as a specification, optimization and distributed execution language for dynamic distributed mashups in varied P2P settings. We also demonstrate our AXML optimizer’s (OptimAX) optimization rules and rewriting engine with a help of GUI. I. SETTING: MASHING UP THE WEB The Web evolution trend known as the “Web 2.0 ” entails
