Summary: Depends on D18672. Ref T13000. This does an on-demand build of the common ngrams table. Plan here is: - Push to `secure`. - Build the common ngrams table here. - See if stuff breaks? If it looks okay on this dataset, we can build out the GC support and try it in production. Test Plan: - Locally, my dataset has a bunch of `bin/lipsum` tasks with similar, common words. - Verified that ipsum terms now skip ngrams. For "lorem ipsum" search performance actually IMPROVED by skipping the ngrams table (12s to 9s). - Queried for normal terms, got very fast results using the ngram table, as normal. Reviewers: amckinley Reviewed By: amckinley Maniphest Tasks: T13000 Differential Revision: https://secure.phabricator.com/D18673