i want to set up a SPARQL Endpoint with different RDBMS as a background. Since the data in the RDBMS is updated regulary (and its quite a lot) I wouldn't want to replicate all as RDF. Instead I would like to set up a SPARQL-SQL-Mapper. After reading publications from the W3C on the topic (W3C RDB2RDF) and some research of my own I tried the D2R Server and Virtuoso.
D2R was very easy to configure and is a very nice tool. However it seems to be a little slow (I still want to run some tests on some other DBs that I am currently using)
Virtuoso on the other hand was very uncomfortable to configure i felt. I was so far only able to get a basic example running with the Virtuoso generated mappings. So far that is not useful at all but I was not able to write a custom mapping including all the necessary steps.
So my question (finally) is: What are your experiences with setting up an SPARQL Endpoint on top of (one or many) RDBMS? Is there a best practice? Whats the best software for the task? Any thoughts...