Executing terms aggregation

The most used bucket aggregation is the terms one. It groups the documents in buckets based on a single term value. This aggregation is often used to narrow down the search using the computed values as filters for the queries.

Getting ready

You need an up-and-running Elasticsearch installation, as we described in the Downloading and installing Elasticsearch recipe in Chapter 2, Downloading and Setup.

To execute curl via the command line, you need to install curl for your operative system.

To correctly execute the following command, you need an index populated with the chapter_08/populate_aggregations.sh script available in the online code.

How to do it...

For executing a term aggregation, we will perform the following steps:

1. We want to calculate the top 10 tags of all the documents: the REST call should be as follows:

           curl -XGET 'http://127.0.0.1:9200/test-index/test-type/_search?  
           pretty&size=0' -d '{ 
               "query": { 
       ...