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Estimating the cardinality of RDF graph patterns

Angela Maduko, Kemafor Anyanwu, Amit Sheth, Paul Schliekelman
2007 Proceedings of the 16th international conference on World Wide Web - WWW '07  
This work proposes a pattern-based summarization framework for estimating the cardinality of RDF graph patterns.  ...  A key factor in optimizing joins is determining the join order which depends on the expected cardinality of intermediate results.  ...  The estimation value of a pattern defines the number of its minimal size super-patterns whose cardinalities are estimable from its cardinality within an ε error.  ... 
doi:10.1145/1242572.1242782 dblp:conf/www/MadukoASS07 fatcat:z52q6llac5fi5flvqoxtxwrkiy

PRESTO: Probabilistic Cardinality Estimation for RDF Queries Based on Subgraph Overlapping [article]

Xin Wang, Eugene Siow, Aastha Madaan, Thanassis Tiropanis
2018 arXiv   pre-print
It is especially challenging for RDF due to the lack of explicit schema and the excessive occurrence of joins in RDF queries.  ...  Existing approaches typically collect statistics based on the counts of triples and estimate the cardinality of a query as the product of its join components, where errors can accumulate even when the  ...  CARDINALITY ESTIMATION Given the RDF graph and the query shown in Figure 1 , the cardinality of the query equals to the number of distinct paths from ax to ey that pass both a2 and d1.  ... 
arXiv:1801.06408v1 fatcat:3zzvom7qi5eexbw7h4hcg3bari

Characteristic sets: Accurate cardinality estimation for RDF queries with multiple joins

Thomas Neumann, Guido Moerkotte
2011 2011 IEEE 27th International Conference on Data Engineering  
We then show experimentally that the new methods are-in the RDF context-highly superior to the estimation methods employed by commercial DBMSs and by the open-source RDF store RDF-3X.  ...  To overcome this lack of appropriate cardinality estimation methods, we introduce characteristic sets together with new cardinality estimation methods based upon them.  ...  ACKNOWLEDGMENT We thank Uwe Steinel for the administration of the three commercial database systems and Sebastian Sindermann for carrying out the experiments with them.  ... 
doi:10.1109/icde.2011.5767868 dblp:conf/icde/NeumannM11 fatcat:mdmhnocwdfevphksufhyzw4lwe

RQ-RDF-3X: Going beyond triplestores

Jyoti Leeka, Srikanta Bedathur
2014 2014 IEEE 30th International Conference on Data Engineering Workshops  
In this paper, we explore the challenges of supporting such richer semantic data by extending the state-of-the-art RDF-3X system.  ...  We describe our implementation of RQ-RDF-3X, a reification and quad enhanced RDF-3X, which involved a significant re-engineering ranging from the set of indexes and their compression schemes to the query  ...  r,c1) has a cardinality of 3 which is smaller than 7 (estimated cardinality obtained after naive extension); therefore, RQ-RDF-3X correctly chooses 3 as the cardinality estimate, which also happens to  ... 
doi:10.1109/icdew.2014.6818337 dblp:conf/icde/LeekaB14 fatcat:zwsepdgldvdaphxm2xdffqtr7e

Towards Efficient Path Query on Social Network with Hybrid RDF Management [article]

Lei Gai, Wei Chen, Zhichao Xu, Changhe Qiu, Tengjiao Wang
2014 arXiv   pre-print
In this hybrid framework, we realize an efficient in-memory algebra operator for property path query using graph traversal, and estimate the cost of this operator to cooperate with existing cost-based  ...  The scalability and exibility of Resource Description Framework(RDF) model make it ideally suited for representing online social networks(OSN).  ...  Property Path Algebra Operator The cost of OpPath operator is the cardinality of result set R(q) for path query pattern q.  ... 
arXiv:1405.6500v2 fatcat:yfyym5stofamvgsc2d6h3757ym

Efficiently Joining Group Patterns in SPARQL Queries [chapter]

María-Esther Vidal, Edna Ruckhaus, Tomas Lampo, Amadís Martínez, Javier Sierra, Axel Polleres
2010 Lecture Notes in Computer Science  
In SPARQL, conjunctive queries are expressed by using shared variables across sets of triple patterns, also called basic graph patterns.  ...  Thus, it may be significantly more efficient to independently evaluate each of the groups, and then merge the resulting sets, than linearly joining all triples in a basic graph pattern.  ...  We thank Andy Seaborne for his advice on the installation of the different Jena engines.  ... 
doi:10.1007/978-3-642-13486-9_16 fatcat:6um6ymltwveizgxsa6snarelcu

Characteristic sets profile features: Estimation and application to SPARQL query planning

Lars Heling, Maribel Acosta, Sabrina Kirrane, Axel-Cyrille Ngonga Ngomo
2022 Semantic Web Journal  
RDF dataset profiling is the task of extracting a formal representation of a dataset's features.  ...  Such features may cover various aspects of the RDF dataset ranging from information on licensing and provenance to statistical descriptors of the data distribution and its semantics.  ...  Efficiency of CSPF computation Part of the motivation of this work is the fact that computing and estimating CSPF over samples of the original graph reduces the computational effort.  ... 
doi:10.3233/sw-222903 fatcat:r6pglo7okzep3h7774klq2ssou

Highly Parallel SPARQL Engine for RDF [chapter]

Fan Feng, Weikang Zhou, Ding Zhang, Jinhui Pang
2020 Communications in Computer and Information Science  
Machine learning algorithms were applied to make time predictions of queries and reasonably group them, and further make reasonable estimates of the memory footprint of the queries to arrange the order  ...  Experiments show that the engine can optimize time and maximize the use of memory when processing batch SPARQL queries.  ...  This work is supported by Big Data Research Foundation of PICC.  ... 
doi:10.1007/978-981-15-7981-3_5 fatcat:axncaghjxncmpcss4gvkzksfgu

Join Size Estimation on Boolean Tensors of RDF Data

Saskia Metzler, Pauli Miettinen
2015 Proceedings of the 24th International Conference on World Wide Web - WWW '15 Companion  
For example, estimating the size of the results for different join queries becomes much simpler.  ...  The Resource Description Framework (RDF) represents information as subject-predicate-object triples. These triples are commonly interpreted as a directed labelled graph.  ...  to estimate the cardinalities of sparql joins.  ... 
doi:10.1145/2740908.2742738 dblp:conf/www/MetzlerM15 fatcat:xgatvgu4fbhprkf5qf7h3rbdau

Specific Queries Optimization Using Jaya Approach

Sahil Saharan, J.S. Lather, R. Radhakrishnan
2018 International Journal of Modern Education and Computer Science  
The focus of this paper is to optimize the specific type of the query called Cyclic query and star query on main-memory RDF data model using ARQ query engine of Jena.  ...  For the considered problem, we ruminate a Jaya algorithm for rearrangement of the order of triple pattern and also compare the results with an already proposed approach in the literature.  ...  join values using selectivity based on estimated cardinality and third is to the construction of cost matrix using these estimated join values and estimated cardinality values.  ... 
doi:10.5815/ijmecs.2018.03.05 fatcat:slhlcxs46ndwfc36nal4swy5de

Efficient Query Processing in RDF Databases [chapter]

Andrey Gubichev, Thomas Neumann
2014 Emerging Directions in Database Systems and Applications  
Furthermore, we present a novel RDF statistical synopsis that accurately estimates cardinalities in large SPARQL queries.  ...  Our experiments show that this algorithm is highly superior to the state-of-the-art SPARQL optimization approaches, including the RDF-3X's original Dynamic  ...  Then, for every group of triple patterns we estimate its cardinality using characteristic sets.  ... 
doi:10.1201/b16859-8 fatcat:xu6mdl3uvnhmzcvzdbap2i2eiq

R3F: RDF triple filtering method for efficient SPARQL query processing

Kisung Kim, Bongki Moon, Hyoung-Joo Kim
2013 World wide web (Bussum)  
The most important part of SPARQL query processing is its method of subgraph pattern matching.  ...  In order to address this problem, we propose an RDF Triple Filtering (R3F) method that exploits the graph-structural information of RDF data.  ...  (2) the estimated cardinalities of the RFLT operators.  ... 
doi:10.1007/s11280-013-0253-1 fatcat:pqi4li4yrnbhlfvqjf4y6lpese

SPLODGE: Systematic Generation of SPARQL Benchmark Queries for Linked Open Data [chapter]

Olaf Görlitz, Matthias Thimm, Steffen Staab
2012 Lecture Notes in Computer Science  
We evaluate the adequacy of our methodology and the query generation strategy by applying them on the 2011 billion triple challenge data set.  ...  The distributed and heterogeneous nature of Linked Open Data requires flexible and federated techniques for query evaluation.  ...  The research leading to these results has received funding from the European Community's Seventh Frame Programme under grant agreement No 257859, ROBUST.  ... 
doi:10.1007/978-3-642-35176-1_8 fatcat:5rzblxeufffbbmzan6fmpguz6i

Towards efficient SPARQL query processing on RDF data

Chang Liu, Haofen Wang, Yong Yu, Linhao Xu
2010 Tsinghua Science and Technology  
The optimization collects a set of RDF statistics for estimating the execution cost of the query plan.  ...  1 s and is extremely efficient and scalable in comparison with previous best state-of-the-art RDF stores.  ...  Since all the leaf nodes are index scans, their cost can be estimated based on the input cardinality. For example, given a triple pattern <?  ... 
doi:10.1016/s1007-0214(10)70108-5 fatcat:6v6ypsvikzemtblic6rr4it6wu


Sairam Gurajada, Stephan Seufert, Iris Miliaraki, Martin Theobald
2014 Proceedings of the 2014 ACM SIGMOD international conference on Management of data - SIGMOD '14  
Our engine, coined "TriAD", combines joinahead pruning via a novel form of RDF graph summarization with a locality-based, horizontal partitioning of RDF triples into a gridlike, distributed index structure  ...  We investigate a new approach to the design of distributed, sharednothing RDF engines.  ...  Thus, let Card(Ri) be the precomputed cardinality of a query pattern Ri over the RDF data graph, and let |Cs|, |Co| be the cardinalities of its subject s and object o, respectively, obtained from the precomputed  ... 
doi:10.1145/2588555.2610511 dblp:conf/sigmod/GurajadaSMT14 fatcat:tejrebkzsnaa7nspnbmkmorqtm
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