https://www.elastic.co/guide/en/elasticsearch/guide/current/_finding_exact_values.html

https://www.elastic.co/blog/frame-of-reference-and-roaring-bitmaps

https://blog.madewithlove.be/post/basic-understanding-of-text-search/

https://qbox.io/blog/introduction-to-elasticsearch-analyzers

http://www.elasticsearchtutorial.com/basic-elasticsearch-concepts.html

http://2010.berlinbuzzwords.de/sites/2010.berlinbuzzwords.de/files/busch_bbuzz2010.pdf

https://www.elastic.co/blog/found-elasticsearch-from-the-bottom-up

http://blog.mikemccandless.com/2011/02/visualizing-lucenes-segment-merges.html

elastic search interval