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Triple pattern join cardinality estimations over HDT with enhanced metadata

Elena Wössner, Chang Qin, J. D. Fernández, Maribel Acosta
2019
In this work, we present HDT-stats, an extension to the HDT operations, to compute further metadata when evaluating triple patterns over RDF graphs represented with HDT.  ...  Then, we propose a novel model that relies on the HDT-stats metadata, as well as the distinct position of SPARQL variables, to estimate the cardinality of joins between triple patterns.  ...  Based on this metadata, we propose a novel cardinality estimation model that considers the type of the join between pairs of triple patterns.  ... 
doi:10.5445/ir/1000100184 fatcat:74gyeelbxvckroytw5ccxilyzy

Toward sustainable publishing and querying of distributed Linked Data archives

Miel Vander Sande, Ruben Verborgh, Patrick Hochstenbach, Herbert Van de Sompel
2018 Journal of Documentation  
These project mostly aimed at bibliographic metadata enrichment, data interlinking, source referencing, unifying data from various sources, and enhancing existing applications.  ...  To improve on the discussed status quo, a novel approach for publishing Linked Data is proposed and demonstrated by means of an archive of DBpedia versions, which is queried in combination with other Linked  ...  In addition, it can estimate the cardinality of such patterns efficiently, which is useful for optimizing query planning over HDT files.  ... 
doi:10.1108/jd-03-2017-0040 fatcat:5shepjkynbfqhojlz4kgn2lhya

SMART-KG: Hybrid Shipping for SPARQL Querying on the Web

Amr Azzam, Javier D. Fernández, Maribel Acosta, Martin Beno, Axel Polleres
2020 Proceedings of The Web Conference 2020  
Alternative solutions such as Triple Pattern Fragments (TPF) attempt to tackle the problem of availability by pushing query processing workload to the client side, but suer from unnecessary transfer of  ...  irrelevant data on complex queries with large intermediate results.  ...  Join order is determined by the cardinality of triple patterns, where smaller triple patterns are evaluated rst. 9 Note that Q 00 s also includes triple patterns with predicate variables, i.e., p 2 V  ... 
doi:10.1145/3366423.3380177 dblp:conf/www/AzzamFABP20 fatcat:irrxzpvodzgu3kogwnbwvlwcfy

Robust query processing for linked data fragments

Lars Heling, Maribel Acosta, Axel-Cyrille Ngonga Ngomo, Muhammad Saleem, Ruben Verborgh
2022 Semantic Web Journal  
These operators adapt their join strategy in response to possible cardinality estimation errors.  ...  However, these heuristics are prone to potential estimation errors based on the metadata which can lead to inefficient query executions with a high number of requests, large amounts of data transferred  ...  The number of estimated triples matching each triple pattern (count) provided as metadata from the TPF server is also indicated in Listing 1.  ... 
doi:10.3233/sw-212888 fatcat:zy3vkeufcjeoxfyb42bwz3gfvi

Management of Big Semantic Data [chapter]

Javier Fernández, Mario Arias, Miguel Martínez-Prieto, Claudio Gutiérrez
2013 Big Data Computing  
Joining Basic Triple Patterns. All this infrastructure enables basic triple patterns to be resolved, in compressed space, at higher levels of the hierarchy of memory.  ...  From a metadata point of view, OWL can be considered a rich vocabulary with high expressive power (classes, properties, relations, cardinality, equality, constraints, etc.) .  ... 
doi:10.1201/b16014-7 fatcat:vasx7wu5njgprddsu7c4pvr2q4

Binary RDF for scalable publishing, exchanging and consumption in the web of data

Javier D. Fernández
2012 Proceedings of the 21st international conference companion on World Wide Web - WWW '12 Companion  
This section presents how HDT can be enhanced with additional indexes at consumption time in order to resolve all kind of triple pattern in SPARQL.  ...  Merge join is used when the results of both triple patterns are sorted by the join variable.  ...  HDT-FoQ Generation HDT-FoQ starts out from the idea of exchanging HDT with the D comp dictionary (see Chapter 10) and the Bitmap Triples (see Chapter 13) .  ... 
doi:10.1145/2187980.2187997 dblp:conf/www/Fernandez12 fatcat:j2rclthkdnanfbbnwym4smlno4

Triple Pattern Fragments: A low-cost knowledge graph interface for the Web

Ruben Verborgh, Miel Vander Sande, Olaf Hartig, Joachim Van Herwegen, Laurens De Vocht, Ben De Meester, Gerald Haesendonck, Pieter Colpaert
2016 Journal of Web Semantics  
This article describes the Linked Data Fragments framework to analyze Web interfaces to Linked Data and uses this framework as a basis to define Triple Pattern Fragments.  ...  To mitigate this shortage of live queryable Linked Data, we designed a low-cost Triple Pattern Fragments interface for servers, and a client-side algorithm that evaluates SPARQL queries against this interface  ...  Next, we determine the triple pattern tp ∈ B i with the smallest estimated number of matches (line 10).  ... 
doi:10.1016/j.websem.2016.03.003 fatcat:e5zovrhg2rhork4k7ocfz36tbu

Triple Pattern Fragments: A Low-Cost Knowledge Graph Interface for the Web

Ruben Verborgh, Miel Vander Sande, Olaf Hartig, Joachim Van Herwegen, Laurens De Vocht, Ben De Meester, Gerald Haesendonck, Pieter Colpaert
2016 Social Science Research Network  
This article describes the Linked Data Fragments framework to analyze Web interfaces to Linked Data and uses this framework as a basis to define Triple Pattern Fragments.  ...  To mitigate this shortage of live queryable Linked Data, we designed a low-cost Triple Pattern Fragments interface for servers, and a client-side algorithm that evaluates SPARQL queries against this interface  ...  Next, we determine the triple pattern tp ∈ B i with the smallest estimated number of matches (line 10).  ... 
doi:10.2139/ssrn.3199223 fatcat:vk5bysryjbdrhfg2bzxpg73k74

Storage, Indexing, Query Processing, and Benchmarking in Centralized and Distributed RDF Engines: A Survey [article]

Waqas Ali, Muhammad Saleem, Bin Yao, Aidan Hogan, Axel-Cyrille Ngonga Ngomo
2020 arXiv   pre-print
Finally, query execution involving different join orders significantly affects the query response time.  ...  This type of query plans is based on the cardinality (estimated or actual) of triple patterns and join between triple patterns.  ...  The join order is based on the cardinality estimations.  ... 
arXiv:2009.10331v2 fatcat:ou4nctjyj5c6jbh4osclewj62e

Multidimensional enrichment of spatial RDF data for SOLAP

Nurefşan Gür, Torben Bach Pedersen, Katja Hose, Mikael Midtgaard, Boyan Brodaric
2021 Semantic Web Journal  
statistical data sets might have spatial information, such as coordinates, the lack of spatial semantics and spatial multidimensional concepts in QB4OLAP and QB prevents users from employing SOLAP queries over  ...  Furthermore, we present and evaluate a wide range of enrichment algorithms and apply them on a non-trivial real-world use case involving governmental open data with complex geometry types.  ...  Furthermore, to achieve scalable querying and runtime optimization, new research directions can be taken with binary serialization of the QB4SOLAP RDF data such as header dictionary triples (HDT), which  ... 
doi:10.3233/sw-210423 fatcat:icj6rcryyzczdb54f5fupadwru

SMART-KG: Hybrid Shipping for SPARQL Querying on the Web

A. Azzam, J. D. Fernández, M. Acosta, M. Beno, A. Polleres
2020
Alternative solutions such as Triple Pattern Fragments (TPF) attempt to tackle the problem of availability by pushing query processing workload to the client side, but suffer from unnecessary transfer  ...  of irrelevant data on complex queries with large intermediate results.  ...  Join order is determined by the cardinality of triple patterns, where smaller triple patterns are evaluated first.  ... 
doi:10.5445/ir/1000122092 fatcat:3ve2d7rdqvd7lbr7nbmpj5zsni

Semantic technologies for distributed information systems

Peter Haase
2007
The SPARQL query language is based on matching graph patterns. The simplest graph pattern is the triple pattern.  ...  It does support the relational operations of selection (FILTER clause), projection (SELECT clause) and cartesian product (combination of triple patterns in the WHERE clause) as well as union (joining patterns  ... 
doi:10.5445/ksp/1000005707 fatcat:rd4evmuklvghzkoofoxhmlxfny

Semantic technologies for distributed information systems

Peter Haase
2006
Throughout the work, we will refer to the implementation of the Bibster system a Peer-to-Peer system for sharing bibliographic metadata to demonstrate the bene ts of semantic technologies. iii iv  ...  Second, we show how ontology evolution allows us to deal with changes in the information in a consistent manner.  ...  The SPARQL query language is based on matching graph patterns. The simplest graph pattern is the triple pattern.  ... 
doi:10.5445/ir/1000005905 fatcat:abfnxsfepfactjte6i7x7th4eu