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Elasticsearch Guide [8.1] » Query DSL » Term-level queries » Prefix query
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Prefix query

Returns documents that contain a specific prefix in a provided field.

Example request

The following search returns documents where the user.id field contains a term that begins with ki.

GET /_search
{
  "query": {
    "prefix": {
      "user.id": {
        "value": "ki"
      }
    }
  }
}

Top-level parameters for prefix

<field>
(Required, object) Field you wish to search.

Parameters for <field>

value
(Required, string) Beginning characters of terms you wish to find in the provided <field>.
rewrite
(Optional, string) Method used to rewrite the query. For valid values and more information, see the rewrite parameter.
case_insensitive [7.10.0] Added in 7.10.0.
(Optional, Boolean) Allows ASCII case insensitive matching of the value with the indexed field values when set to true. Default is false which means the case sensitivity of matching depends on the underlying field’s mapping.

Notes

Short request example

You can simplify the prefix query syntax by combining the <field> and value parameters. For example:

GET /_search
{
  "query": {
    "prefix" : { "user" : "ki" }
  }
}

Speed up prefix queries

You can speed up prefix queries using the index_prefixes mapping parameter. If enabled, Elasticsearch indexes prefixes between 2 and 5 characters in a separate field. This lets Elasticsearch run prefix queries more efficiently at the cost of a larger index.

Allow expensive queries

Prefix queries will not be executed if search.allow_expensive_queries is set to false. However, if index_prefixes are enabled, an optimised query is built which is not considered slow, and will be executed in spite of this setting.

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