store

By default, field values are indexed to make them searchable, but they are not stored. This means that the field can be queried, but the original field value cannot be retrieved.

Usually this doesn’t matter. The field value is already part of the _source field, which is stored by default. If you only want to retrieve the value of a single field or of a few fields, instead of the whole _source, then this can be achieved with source filtering.

In certain situations it can make sense to store a field. For instance, if you have a document with a title, a date, and a very large content field, you may want to retrieve just the title and the date without having to extract those fields from a large _source field:

response = client.indices.create(
  index: 'my-index-000001',
  body: {
    mappings: {
      properties: {
        title: {
          type: 'text',
          store: true
        },
        date: {
          type: 'date',
          store: true
        },
        content: {
          type: 'text'
        }
      }
    }
  }
)
puts response

response = client.index(
  index: 'my-index-000001',
  id: 1,
  body: {
    title: 'Some short title',
    date: '2015-01-01',
    content: 'A very long content field...'
  }
)
puts response

response = client.search(
  index: 'my-index-000001',
  body: {
    stored_fields: [
      'title',
      'date'
    ]
  }
)
puts response

PUT my-index-000001
{
  "mappings": {
    "properties": {
      "title": {
        "type": "text",
        "store": true 
      },
      "date": {
        "type": "date",
        "store": true 
      },
      "content": {
        "type": "text"
      }
    }
  }
}

PUT my-index-000001/_doc/1
{
  "title":   "Some short title",
  "date":    "2015-01-01",
  "content": "A very long content field..."
}

GET my-index-000001/_search
{
  "stored_fields": [ "title", "date" ] 
}