Minimization of tree pattern queries with constraints

Chan, Chee-Yong

doi:10.1145/1376616.1376678

Cited by 19 publications

(39 citation statements)

References 16 publications

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“…These problems have been well studied for XPath (e.g., [9], [24], [36]). However, we are not aware of previous work on these problems for graph pattern queries.…”

Section: Contributions and Roadmapmentioning

confidence: 99%

“…It has been studied for, e.g., relational conjunctive queries [2] and XML tree pattern queries [9], [24], [36]. For all the reasons that query minimization is important for relational queries and XML queries, we also need to study minimization of graph queries.…”

Section: B Minimizing Graph Pattern Queriesmentioning

confidence: 99%

“…In a reversed topological order (lines [6][7][8][9][10][11][12][13][14], JoinMatch repeatedly removes from mat() those nodes that do not make a match, by using premv() from procedure Join. There are two SCCs: SCC 1 and SCC 2 , consisting of nodes { } and { , }, respectively.…”

Section: Examplementioning

confidence: 99%

“…In addition, it constructs the partition-relation pair ⟨par, rel⟩ (line 6); it also initializes rmv() for each query edge (line 7), a step similar to its counterpart in JoinMatch. It then iteratively selects and processes those query edges with a nonempty remove set, i.e., edges for which the match set can be refined (lines [8][9][10][11][12][13][14]. The set of blocks par is split based on rmv( ) Input for each…”

Section: B Split-based Algorithmmentioning

confidence: 99%

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Adding regular expressions to graph reachability and pattern queries

Fan

et al. 2011

2011 IEEE 27th International Conference on Data Engineering

114

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Abstract-It is increasingly common to find graphs in which edges bear different types, indicating a variety of relationships. For such graphs we propose a class of reachability queries and a class of graph patterns, in which an edge is specified with a regular expression of a certain form, expressing the connectivity in a data graph via edges of various types. In addition, we define graph pattern matching based on a revised notion of graph simulation. On graphs in emerging applications such as social networks, we show that these queries are capable of finding more sensible information than their traditional counterparts. Better still, their increased expressive power does not come with extra complexity. Indeed, (1) we investigate their containment and minimization problems, and show that these fundamental problems are in quadratic time for reachability queries and are in cubic time for pattern queries. (2) We develop an algorithm for answering reachability queries, in quadratic time as for their traditional counterpart. (3) We provide two cubictime algorithms for evaluating graph pattern queries based on extended graph simulation, as opposed to the NP-completeness of graph pattern matching via subgraph isomorphism. (4) The effectiveness, efficiency and scalability of these algorithms are experimentally verified using real-life data and synthetic data.

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“…These problems have been well studied for XPath (e.g., [9], [24], [36]). However, we are not aware of previous work on these problems for graph pattern queries.…”

Section: Contributions and Roadmapmentioning

confidence: 99%

Section: B Minimizing Graph Pattern Queriesmentioning

confidence: 99%

Section: Examplementioning

confidence: 99%

Section: B Split-based Algorithmmentioning

confidence: 99%

See 2 more Smart Citations

Adding regular expressions to graph reachability and pattern queries

Fan

et al. 2011

2011 IEEE 27th International Conference on Data Engineering

114

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“…In addition to theoretical interests on complexity [2], minimization [8] of reformulation of queries and other constraints [19] in the presence of materialized views, practical and scalable solutions to exploiting views are intensively studied, including [6]. In this paper, we focus on the view exploitation [17] and particularly answer which views are usable for a given RDF pattern, covering view selection in view design and rewriting for view exploitation [6].…”

Section: Related Workmentioning

confidence: 99%

RDF pattern matching using sortable views

Chong

Chen

Zhang

et al. 2012

Proceedings of the 21st ACM International Conference on Information and Knowledge Management

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In the last few years, RDF is becoming the dominating data model used in semantic web for knowledge representation and inference. In this paper, we revisit the problem of pattern matching query in RDF model, which is usually expensive in efficiency due to the huge cost on join operations. To alleviate the efficiency pain, view materialization techniques are usually deployed to accelerate the query processing. However, given an arbitrary view, it remains difficult to identify how to reuse the view for a particular query, because of the NP-hardness behind the algorithm matching patterns and views. To fully exploit the benefit of the materialized views, we propose a new paradigm to enhance the effectiveness of the materialized view. Instead of choosing materialized views in arbitrary form, our paradigm aims to select the views only if they are sortable. The property of sortability raises huge gains on the pattern-view matching, bringing down the cost to linear complexity in terms of the pattern size. On the other side, the costs on identifying sortable views and searching over the views using inverted index are affordable. Moreover, sortable views generally improve the overall performance of pattern matching, by means of a cost model used to optimize the query rewriting on the most appropriate views. Finally, we demonstrate extensive experimental results to verify the superiority of our proposal on both efficiency and effectiveness.

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