Elasticsearch 7 Quick Start Guide

Searching as few fields as possible

A query slows as the number of fields it targets increases. To overcome this, it is better to copy the values into a single field at index time, and then search through the field at search time. This process can be automated with the copy-to directive of mappings. In the following example, an index contains the titles and authors of books. The query indexes both values into the same name_and_title field. Please refer to the following example:

PUT books{  "mappings": {    "properties": {      "name_and_title": {        "type": "text"      },      "name": {        "type": "text",        "copy_to": "name_and_title"      },      "title": {        "type": "text",        "copy_to": "name_and_title"      }    }  }}

In the preceding query, we are copying the name and title field into ...