What is the main advantage of using VPAs as underlying execution model?

One of11 http://www.cs.washington.edu/research/xmldatasets/the main advantages of using VPAs as the underlying execution model is that the authors can take advantage of the rich literature on efficient evaluation of VPAs.

What was the problem declared as a challenge in 2006?

· · · Even for these more modest extensions, however, efficient implementation remained an issue: in 2006, the following open problem was declared as a challenge for the field [31]: Efficient algorithms for computing the transitive closure of XPath path expressions.

What is the cost of full determinization of a VPA?

In general, full determinization of a VPA is an expensive process, which can increase the number of states from O(n) to O(2n 2) [2].

What is the way to skip intermediate subelements?

In order to skip all the intermediate subelements, the automatically generated VPAs contain several states with incoming and outgoing -transitions.

Open AccessProceedings Article10.1145/2213836.2213866

High-performance complex event processing over XML streams

Barzan Mozafari, +2 more

- 20 May 2012

- pp 253-264

TL;DR: This paper presents the XSeq language and system that support CEP on XML streams, via an extension of XPath that is both powerful and amenable to an efficient implementation, and provides formal results on its expressiveness and complexity.

Abstract: Much research attention has been given to delivering high-performance systems that are capable of complex event processing (CEP) in a wide range of applications. However, many current CEP systems focus on processing efficiently data having a simple structure, and are otherwise limited in their ability to support efficiently complex continuous queries on structured or semi-structured information. However, XML streams represent a very popular form of data exchange, comprising large portions of social network and RSS feeds, financial records, configuration files, and similar applications requiring advanced CEP queries. In this paper, we present the XSeq language and system that support CEP on XML streams, via an extension of XPath that is both powerful and amenable to an efficient implementation. Specifically, the XSeq language extends XPath with natural operators to express sequential and Kleene-* patterns over XML streams, while remaining highly amenable to efficient implementation. XSeq is designed to take full advantage of recent advances in the field of automata on Visibly Pushdown Automata (VPA), where higher expressive power can be achieved without compromising efficiency (whereas the amenability to efficient implementation was not demonstrated in XPath extensions previously proposed).We illustrate XSeq's power for CEP applications through examples from different domains, and provide formal results on its expressiveness and complexity. Finally, we present several optimization techniques for XSeq queries. Our extensive experiments indicate that XSeq brings outstanding performance to CEP applications: two orders of magnitude improvement are obtained over the same queries executed in general-purpose XML engines.

AI Agents for this Paper

Find similar papers on Google Scholar, PubMed and Arxiv
Write a critical review of this paper
Analyze citations of this paper to find unaddressed research gaps

Most frequently asked questions

1. What is the main source of nondeterminism in the transition table?

Since self-loops in the transition table are the main source of nondeterminism, the XSeq’s compile-time optimizer removes such edges from the generated VPA, whenever possible.

2. What is the way to handle the VPAs?

Handling other constructs Union, intersection (equivalently, node tests) and negation can all be implemented with their correspondingoperations on the intermediary VPAs, as VPAs are closed under union, intersection and complementation.

3. What is the way to remove self-loops from the VPA?

For instance, if the authors know that book nodes only contain two subelements, say title followed by year, the optimizer replaces E1 with 3 new states (without any self-loop) to explicitly skip the title’s open, text and closed tags.

4. Why have the authors used the same run-time engine for XSeq queries?

Because of the excellent VPA execution performance achieved by K*SQL [21], the authors have used the same run-time engine for XSeq queries once they are compiled into a VPA (see Section 7).

Figure 4: VPAs for (a) /son@Bdate, (b) /daughter son, (c) //book[year = 2000], and (d) //book[@title = ‘mytitle′]

Figure 5: Visual correspondence of VPA states and XSeq axes.

Figure 9: The effect of different types of queries on (a) Total query execution time, (b) Throughput in terms of tuple processing, and (c) Throughput in terms of datasize.

Figure 1: A query in XPath 2.0/XQuery for a sequence of ‘falling price’ in Nasdaq’s XML.

Figure 8: Effect of different types of XSeq queries on total execution time (a) and memory usage (b).

Citations

•Proceedings Article•10.1145/2588555.2593671

On complexity and optimization of expensive queries in complex event processing

Haopeng Zhang, +2 more

- 18 Jun 2014

TL;DR: This study begins by analyzing the complexity of pattern queries, with a focus on the fundamental understanding of which features make pattern queries more expressive and at the same time more computationally expensive, and provides key insights for a series of optimizations to mitigate those bottlenecks.

...read moreread less

175

•Journal Article•10.14778/2732296.2732298

An efficient publish/subscribe index for e-commerce databases

Dongxiang Zhang, +2 more

- 01 Apr 2014

TL;DR: An efficient in-memory index that is scalable to the volume and update of subscriptions, the arrival rate of events and the variety of subscribable attributes is proposed and the superiority of the index over state-of-the-art methods is demonstrated.

...read moreread less

Real time contextual collective anomaly detection over multiple data streams

Yexi Jiang, +3 more

- 01 Jan 2014

TL;DR: This paper proposes a framework to discover a new type of anomaly called contextual collective anomaly over a collection of data streams in real time that can be seamlessly integrated with real time monitoring systems to timely and accurately identify the anomalies.

...read moreread less

•Journal Article•10.1145/2536779

High-performance complex event processing over hierarchical data

Barzan Mozafari, +3 more

- 04 Dec 2013

- ACM Transactions on Database Systems

TL;DR: This article presents the XSeq language and system that support CEP on XML streams, via an extension of XPath that is both powerful and amenable to an efficient implementation, and illustrates its power for CEP applications through examples from different domains and provides formal results on its expressiveness and complexity.

...read moreread less

•Journal Article•10.1016/J.TCS.2015.01.017

Early nested word automata for XPath query answering on XML streams

Denis Debarbieux, +5 more

- 03 May 2015

- Theoretical Computer Science

TL;DR: It turns out that the early query answering algorithm is earliest in practice on most queries from the XPathMark benchmark, and is proved tight upper complexity bounds on time and space consumption.

...read moreread less

...

Expand

References

Journal Article•10.1137/0206024

Fast Pattern Matching in Strings

Donald E. Knuth, +2 more

- 01 Jun 1977

- SIAM Journal on Computing

TL;DR: An algorithm is presented which finds all occurrences of one given string within another, in running time proportional to the sum of the lengths of the strings, showing that the set of concatenations of even palindromes, i.e., the language $\{\alpha \alpha ^R\}^*$, can be recognized in linear time.

...read moreread less

3.4K

•Reference Book•10.1007/978-0-387-39940-9

Encyclopedia of Database Systems

Ling Liu, +1 more

- 29 Sep 2009

- Springer US

TL;DR: This comprehensive reference contains 1,300 illustrated entries, organized alphabetically, providing easy access to important concepts relevant information on all aspects of very large databases, data management, and database systems, including areas of current interest and research results of historical significance.

...read moreread less

1.9K

•Book

The Power of Events: An Introduction to Complex Event Processing in Distributed Enterprise Systems

David C. Luckham

- 01 May 2002

TL;DR: Some possible long-term future roles of CEP in the Information Society are discussed along with the need to develop rule-based event hierarchies on a commercial basis to make those applications possible.

...read moreread less

1.5K

Proceedings Article•10.1145/1142473.1142520

High-performance complex event processing over streams

Eugene Wu, +2 more

- 27 Jun 2006

TL;DR: This paper proposes a complex event language that significantly extends existing event languages to meet the needs of a range of RFID-enabled monitoring applications and describes a query plan-based approach to efficiently implementing this language.

...read moreread less

954

•Journal Article•10.1145/1516512.1516518

Adding nesting structure to words

Rajeev Alur, +1 more

- 19 May 2009

- Journal of the ACM

TL;DR: In this paper, the authors define nested word automata, which generalize both words and ordered trees, and allow both word and tree operations, and show that the resulting class of regular languages of nested words has all the appealing theoretical properties that the classical regular word languages enjoys: deterministic nestedword automata are as expressive as their non-deterministic counterparts; the class is closed under union, intersection, complementation, concatenation, Kleene-a, prefixes, and language homomorphisms; membership, emptiness, language equivalence are all decidable;

...read moreread less

417

...

Expand

High-performance complex event processing over XML streams

Chat with Paper

AI Agents for this Paper

Most frequently asked questions

1. What is the main source of nondeterminism in the transition table?

2. What is the way to handle the VPAs?

3. What is the way to remove self-loops from the VPA?

4. Why have the authors used the same run-time engine for XSeq queries?

5. What is the main advantage of using VPAs as underlying execution model?

6. What was the problem declared as a challenge in 2006?

7. What is the cost of full determinization of a VPA?

8. What is the way to skip intermediate subelements?

Figures

Citations

On complexity and optimization of expensive queries in complex event processing

An efficient publish/subscribe index for e-commerce databases

Real time contextual collective anomaly detection over multiple data streams

High-performance complex event processing over hierarchical data

Early nested word automata for XPath query answering on XML streams

References

Fast Pattern Matching in Strings

Encyclopedia of Database Systems

The Power of Events: An Introduction to Complex Event Processing in Distributed Enterprise Systems

High-performance complex event processing over streams

Adding nesting structure to words

Related Papers (5)

High-performance complex event processing over streams

High-performance complex event processing over hierarchical data

ZStream: a cost-based query processor for adaptively detecting composite events

On complexity and optimization of expensive queries in complex event processing

Adding nesting structure to words