  To cope with the intractability of answering Conjunctive Queries (CQs) and
solving Constraint Satisfaction Problems (CSPs), several notions of hypergraph
decompositions have been proposed -- giving rise to different notions of width,
noticeably, plain, generalized, and fractional hypertree width (hw, ghw, and
fhw). Given the increasing interest in using such decomposition methods in
practice, a publicly accessible repository of decomposition software, as well
as a large set of benchmarks, and a web-accessible workbench for inserting,
analyzing, and retrieving hypergraphs are called for.
  We address this need by providing (i) concrete implementations of hypergraph
decompositions (including new practical algorithms), (ii) a new, comprehensive
benchmark of hypergraphs stemming from disparate CQ and CSP collections, and
(iii) HyperBench, our new web-inter\-face for accessing the benchmark and the
results of our analyses. In addition, we describe a number of actual
experiments we carried out with this new infrastructure.
