Indexing Semantic Scholar's Open Research Corpus in Elasticsearch

Semantic Scholar publishes an Open Research Corpus dataset, which currently contains metadata for around 20 million research papers published since 1991.

  1. Create a DigitalOcean droplet using a "one-click apps" image for Docker on Ubuntu (3GB RAM, $15/month) and attach a 200GB data volume ($20/month).
  2. SSH into the instance and start an Elasticsearch cluster running in Docker.
  3. Install esbulk: VERSION=0.4.8; curl -L${VERSION}/esbulk_${VERSION}_amd64.deb -o esbulk.deb && dpkg -i esbulk.deb && rm esbulk.deb
  4. Fetch, unzip and import the Open Research Corpus dataset (inside the zip archive is a license.txt file and a gzipped, newline-delimited JSON file): VERSION=2017-10-30; curl -L${VERSION}/papers-${VERSION}.zip -o && unzip && rm && esbulk -index scholar -type paper -id id -verbose -purge -z < papers-${VERSION}.json.gz && rm papers-${VERSION}.json.gz
  5. While importing, index statistics can be viewed at http://localhost:9200/scholar/_stats?pretty
  6. After indexing, optimise the Elasticsearch index by merging into a single segment: curl -XPOST 'http://localhost:9200/scholar/_forcemerge?max_num_segments=1'
  7. (recommended) Use ufw to prevent external access to the Elasticsearch service and put a web service (e.g. an Express app) in front of it, mapping routes to Elasticsearch queries.