Running the Evaluation

Prerequisites

• Before proceeding, you need the engine (Virtuoso, Blazegraph or QLever) you want to evaluate run on the desired knowledge base (Fbeasy, Freebase or Wikidata). Please consider the respective Tutorials. Note: If you want to evaluate the mixed autocompletion mode on Blazegraph or Virtuoso you also need a running QLever instance with the same knowledge base. This should preferably run on a different machine because of RAM issues, and the port of the QLever instance should be accesible via network.

Download and run the evaluation

• First download and extract the code

  wget http://vldb2021-1807.hopto.org/qlever-evaluation-VLDB-submission.tar.gz
  tar xvzf qlever-evaluation-VLDB-submission.tar.gz
  cd  qlever-evaluation-VLDB-submission/evaluation-autocompletion
  

• Next you need to edit the Dockerfile using a text editor of your choice. Enter the adress + port of your running query engine in lines 33 - 35 (you only need to specify the engines that are actually used correctly. If you have chosen the ports recommended in the Tutorials for Running the engines, these ports should already match. It is important that you use the following formats:

  http://<machine-name>:<port>/      (for qlever)
  http://<machine-name>:<port>/sparql      (for virtuoso)
  http://<machine-name>:<port>/bigdata/sparql      (for blazegraph)
  

Note that you cannot use loopback network devices (127.0.0.1 or localhost) with the docker setup. If you run the engine and the evaluation on the same machine, you can e.g. use the virtual network bridge provided by docker (ip address 172.17.0.1 by default)

• You can then run your evaluation. Specify the values for KB and BACKEND (i.e. the engine) in the second line accordingly. The results are written to a subfolder results/0000-00-00.test , change the OUTPUT_DIR variable in the first line as desired.

  export OUTPUT_DIR=0000-00-00.test && docker build -f Dockerfile -t qlever-evaluation .
  export KB=fbeasy; export BACKEND=blazegraph; export MODE=sensitive;
  docker run -it --rm -e KB=$KB -e MODE=$MODE -e NUM_QUERIES=0 -e BACKEND_TYPE=$BACKEND -v $(pwd)/results/$OUTPUT_DIR:/output --name qlever-evaluation qlever-evaluation;
  

• The Evaluation should run now for some time and the output is shown.

• If you want to run a mixed evaluation, specify MODE=mixed. Note again, that in this case you ALWAYS need a running QLever instance.

• If you want to evaluate all modes on QLever (agnostic, unranked, sensitive, mixed) you can use the following loop (again specify the KB variable accordingly):

  export OUTPUT_DIR=0000-00-00.test; export KB=fbeasy && docker build -f Dockerfile -t qlever-evaluation .
  for MODE in unranked agnostic mixed sensitive ; do docker run -it --rm -e KB=$KB -e MODE=$MODE -e NUM_QUERIES=0 -v $(pwd)/results/$OUTPUT_DIR:/output --name qlever-evaluation qlever-evaluation; done
  

• Note that you can always reuse the same OUTPUT_DIR as the different experiments will be named using the knowledge base, the engine, and the mode.

Inspecting the results

• We have provided an interactive web app that analyzes and visualizes the output of our evaluation script. You need python 3 installed to use it. Inside the qlever-evaluation-VLDB-submission/evaluation-autocompletion folder run:

  python3 -m http.server 9876
  

  (replace 9876 by a free port on your machine). Open a web browser and navigate to http://localhost:9876/www to access the webapp. You should be able to see your previous runs.