Holistic and Compact Selectivity Estimation for Hybrid Queries over RDF Graphs
نویسندگان
چکیده
منابع مشابه
Topic-based Selectivity Estimation for Hybrid Queries over RDF Graphs
The Resource Description Framework (RDF) has become an accepted standard for describing entities on the Web. Many such RDF descriptions are text-rich – besides structured data, they also feature large portions of unstructured text. As a result, RDF data is frequently queried using predicates matching structured data, combined with string predicates for textual constraints: hybrid queries. Evalu...
متن کاملRDF-TX: A Fast, User-Friendly System for Querying the History of RDF Knowledge Bases
Knowledge bases that summarize web information in RDF triples deliver many benefits, including providing access to encyclopedic knowledge via SPARQL queries and end-user interfaces. As the real world evolves, the knowledge base is updated and the evolution history of entities and their properties becomes of great interest to users. Thus, users need query tools of comparable power and usability ...
متن کاملEphedra: SPARQL Federation over RDF Data and Services
Knowledge graph management use cases often require addressing hybrid information needs that involve a multitude of data sources, a multitude of data modalities (e.g., structured, keyword, geospatial search), and availability of computation services (e.g., machine learning and graph analytics algorithms). Although SPARQL queries provide a convenient way of expressing data requests over RDF knowl...
متن کاملSPARQL Query Optimization Using Selectivity Estimation
This poster describes three static SPARQL optimization approaches for in-memory RDF graphs: (1) a selectivity estimation index (SEI) for single query triple patterns; (2) a query pattern index (QPI) for joined triple patterns; and (3) a hybrid optimization approach that combines both indexes. Using the Lehigh University Benchmark (LUBM), we show that the hybrid approach outperforms other SPARQL...
متن کاملEstimating the Cardinality of Conjunctive Queries over RDF Data Using Graph Summarisation
Estimating the cardinality (i.e., the number of answers) of conjunctive queries is particularly difficult in RDF systems: queries over RDF data are navigational and thus tend to involve many joins. We present a new, principled cardinality estimation technique based on graph summarisation. We interpret a summary of an RDF graph using a possible world semantics and formalise the estimation proble...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2014