Zach, I'm unable to answer that question.
D2R's ability to translate SPARQL queries to SQL is limited to certain forms of SPARQL queries. In queries that don't fit these forms, D2R uses ARQ's query planner to generate a query plan where D2R only evaluates part of the query and ARQ takes care of the rest using its standard in-memory query engine. This can sometimes lead to … interesting results where huge intermediate result sets are materialized in memory, or huge numbers of SQL queries are executed in a loop. When this happens, there isn't much you can do except - make your data smaller, - add more memory, - modify/simplify your SPARQL query, - modify/simplify your mapping. Given your parameters – you want to run a fixed benchmark query against a fixed benchmark dataset at a fixed size – you may just be out of luck I'm afraid, until the D2R engine gets another overhaul at some point in the future. The BSBM crew has previously run the benchmark on the D2RQ engine and published its result (including the mapping they used and detailed configuration I believe) – this may have been a previous version of the benchmark and a previous version of D2RQ and smaller dataset size so it may not be relevant, but might be interesting to see how your experience compares to theirs. Best, Richard On 6 Sep 2011, at 21:52, Zach Schweinfurth wrote: > I have been working with the B2BM data generator. I have created a realtional > schema from it at a scale of 284826. I have mapped to the relational schema, > and have been attempting to run queries against D2R. However, I keep either > getting GC Overhead Limit Exceeded or Java heap space errors. I have upped > the -Xmx in the d2r script file to 20 GB, and I have still getting those same > two errors. > > What sort of memory should I expect D2R server to need if I am running > queries against the a relational database created by the BSBM generator at a > scale factor of 284826? > > > Thanks. > > -- > Zachary Schweinfurth > Ontology Engineer > Revelytix, Inc. > > ------------------------------------------------------------------------------ > Malware Security Report: Protecting Your Business, Customers, and the > Bottom Line. Protect your business and customers by understanding the > threat from malware and how it can impact your online business. > http://www.accelacomm.com/jaw/sfnl/114/51427462/_______________________________________________ > d2rq-map-devel mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/d2rq-map-devel ------------------------------------------------------------------------------ Using storage to extend the benefits of virtualization and iSCSI Virtualization increases hardware utilization and delivers a new level of agility. Learn what those decisions are and how to modernize your storage and backup environments for virtualization. http://www.accelacomm.com/jaw/sfnl/114/51434361/ _______________________________________________ d2rq-map-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/d2rq-map-devel
