Mastering Elasticsearch 5.x - Third Edition

Understanding Elasticsearch caching

One of the very important parts of Elasticsearch, although not always visible to the users, is caching. It allows Elasticsearch to store commonly used data in memory and reuse it on demand. Of course, we can't cache everything; we usually have way more data than we have memory, and creating caches may be quite expensive when it comes to performance. In the Instant aggregations in Elasticsearch 5.0 section of Chapter 5, Improving the User Search Experience, we discussed some major improvements done in query parsing and caching. In this chapter, we will look at the different caches exposed by Elasticsearch, and we will discuss how they are used and how we can control their usage. Hopefully, such information will ...