  The number of RDF knowledge graphs available on the Web grows constantly.
Gathering these graphs at large scale for downstream applications hence
requires the use of crawlers. Although Data Web crawlers exist, and general Web
crawlers could be adapted to focus on the Data Web, there is currently no
benchmark to fairly evaluate their performance. Our work closes this gap by
presenting the Orca benchmark. Orca generates a synthetic Data Web, which is
decoupled from the original Web and enables a fair and repeatable comparison of
Data Web crawlers. Our evaluations show that Orca can be used to reveal the
different advantages and disadvantages of existing crawlers. The benchmark is
open-source and available at https://github.com/dice-group/orca.
