Monitoring Elasticsearch

Summary

This chapter addressed some common performance and reliability issues that come up when using Elasticsearch. To reiterate some of the major points in this chapter:

• Always double-check your Elasticsearch cluster's configuration for errors
• Set the fielddata cache size, especially if you see OutOfMemoryError exceptions
• Use the slow log to find what queries run slow on your cluster
• Avoid aggregations on high-cardinality fields (such as millisecond timestamps)
• Be cognizant of your data indexing strategy so that no one index grows too large
• Use index warmers or enable eager_global_ordinals to ensure queries that use the fielddata cache are fast the first time we run them
• If possible, use SSDs on nodes that index data, and avoid storing Elasticsearch ...