There are a few important things when dealing with search or data analysis. We need the results to be precise, we need them to be relevant, and we need them to be returned as soon as possible. If you are a person responsible for designing queries that are run against Elasticsearch, sooner or later, you will find yourself in a position where you will need to improve the performance of your queries. The reasons can vary from hardware-based problems to bad data architecture to poor query design. When writing this book, the benchmark API was only available in the trunk of Elasticsearch, which means that it was not a part of official Elasticsearch distribution. For now we can either use tools like jMeter or ab (the Apache benchmark is http://httpd.apache.org/docs/2.2/programs/ab.html) or use trunk version of Elasticsearch. Please also note that the functionality we are describing can change with the final release, so keeping an eye on http://www.elasticsearch.org/guide/en...