Halyard benchmarking -- how to improve?

Hi Adam @asotona!

I have performed Halyard benchmarking on 1 node setup (i7-3770 3.4GHz, 32GB RAM, normal HDD) --> HDFS + YARN + HBase + Halyard. The querying was done via rdf4j-server SPARQL endpoint. e.g.:

wget -O - "http://halyard/rdf4j-server/repositories/benchmark50?query=select%20%2A%20%7B%3Fs%20%3Fp%20%3Fo%7D%20limit%2010"

I have used FEASIBLE [1] benchmark queries and IGUANA [2]. The configuration for the benchmarking is available in halyard docker repository [3] (iguana-config.tar.bz2).
As you can see from the benchmarking results for the smallest size Halyard could answer only 6 queries, for larger sizes (50 and 100) Halyard answered 0 queries.

From preliminary discussions: it is possible to query Halyard using Java interface and it should improve the performance. Is there any example on how to do that?

[1] http://aksw.org/Projects/FEASIBLE.html
[2] http://aksw.org/Projects/IGUANA.html
[3] https://github.com/earthquakesan/docker-halyard

Start by reviewing the reported FEASIBLE and IGUANA benchmark setup, the linked Halyard Docker configuration, and the Java interface mentioned in the discussion. Reproduce the RDF4J Server queries and compare them with Java-interface usage; the issue is complete only when a concrete, documented improvement or example addresses the benchmark results.