Efficient RDF dictionaries with B+ trees
Gurkirat Singh, Dhawal Upadhyay, Medha Atre · 2018
Resource Description Framework (RDF) graphs are widely used for representing semantically linked data in various domains. Many modern RDF specific storage, indexing, and query optimization systems internally represent the node and edge labels of the RDF graphs as integer IDs. Hence they require dictionaries for converting the strings in a SPARQL query into their corresponding IDs, and the SPARQL query results in the ID form into their corresponding strings. Most of the SPARQL query processing systems have focused on the techniques for indexing of RDF graphs and the optimization of the joins in the SPARQL Basic Graph Pattern (BGP) queries, but the dictionaries that map RDF graph string labels to the IDs and back have remained a neglected component. Dictionaries are important for an "end-to-end user experience" of SPARQL query processing over large RDF graphs.