Elasticsearch and Joining

Elasticsearch and Joining by Felix Hürlimann.

From the post:

With the success of elasticsearch, people, including us, start to explore the possibilities and mightiness of the system. Including border cases for which the underlying core, Lucene, never was originally intended or optimized for. One of the many requests that come up pretty quickly is the whish for joining data across types or indexes, similar to an SQL join clause that combines records from two or more tables in a database. Unfortunately full join support is not (yet?) available out of the box. But there are some possibilities and some attempts to solve parts of issue. This post is about summarizing some of the ideas in this field.

To illustrate the different ideas, let’s work with the following example: we would like to index documents and comments with a one to many relationship between them. Each comment has an author and we would like to answer the question: Give me all documents that match a certain query and a specific author has commented on it.

A variety of options are explored, including some new features of Elasticsearch.

Would you model documents with comments as an association?

Would you query on roles when searching for such a comment by a specific author on such a document?

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