In this chapter, we discussed Elasticsearch and understood the common types of indexation and search problems that you may encounter. You learned how to interact with Elasticsearch using its REST API to index and retrieve the documents. We looked at the Elasticsearch mapping API. Understanding its data types will help you to leverage data type-specific queries.

You got an understanding of what is inverted index and how Elasticsearch indexes data after tokenizing and filtering input. You learned how to use built-in analyzers and create custom analyzers that meet your use-case requirements.

We explored the Query DSL module of Elasticsearch by walking through various practical examples of Elasticsearch query types. At the end of the chapter, we discussed the power of aggregation with real-world examples in order to leverage the analytic capabilities of Elasticsearch.

So far in the book, you learned how to get the data from HDFS to Elasticsearch. You have seen how to perform exploratory...