Tangential, but for anyone looking to utilize Elasticsearch in production, I highly recommend “On-Site Search Design Patterns for E-Commerce”[0]

I was familiar with both inverted indexes and Elasticsearch at a conceptual level, but this overview helped me improve our search (rankings, facets, etc.) much faster than I would have otherwise.

[0]https://project-a.github.io/on-site-search-design-patterns-f...