Type to search.

index_prefixes

Serverless

Elastic Cloud Serverless projects are autoscaled environments, fully managed by Elastic and available on Elastic Cloud.

Availability

  • Generally available

    This functionality is generally available and ready for production usage.

Serverless interfaces and procedures might differ from classic Elastic Stack deployments.

Stack

The Elastic Stack includes Elastic's core products such as Elasticsearch, Kibana, Logstash, and Beats.

Availability

  • Generally available

    This functionality is generally available and ready for production usage.

Unless stated otherwise on the page, this functionality is available when your Elastic Stack is deployed on Elastic Cloud Hosted, Elastic Cloud Enterprise, Elastic Cloud on Kubernetes, and self-managed environments.

This documentation corresponds to the latest patch available for each minor version. If you're not using the latest patch, check the release notes for changes.

The index_prefixes parameter enables the indexing of term prefixes to speed up prefix searches. It accepts the following optional settings:

min_chars
The minimum prefix length to index. Must be greater than 0, and defaults to 2. The value is inclusive.
max_chars
The maximum prefix length to index. Must be less than 20, and defaults to 5. The value is inclusive.

This example creates a text field using the default prefix length settings:

JSON 
PUT my-index-000001
{
  "mappings": {
    "properties": {
      "body_text": {
        "type": "text",
        "index_prefixes": { }
      }
    }
  }
}
  1. An empty settings object will use the default min_chars and max_chars settings

This example uses custom prefix length settings:

JSON 
PUT my-index-000001
{
  "mappings": {
    "properties": {
      "full_name": {
        "type": "text",
        "index_prefixes": {
          "min_chars" : 1,
          "max_chars" : 10
        }
      }
    }
  }
}

index_prefixes parameter instructs Elasticsearch to create a subfield "._index_prefix". This field will be used to do fast prefix queries. When doing highlighting, add "._index_prefix" subfield to the matched_fields parameter to highlight the main field based on the found matches of the prefix field, like in the request below:

JSON 
GET my-index-000001/_search
{
  "query": {
    "prefix": {
      "full_name": {
        "value": "ki"
      }
    }
  },
  "highlight": {
    "fields": {
      "full_name": {
        "matched_fields": ["full_name._index_prefix"]
      }
    }
  }
}