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

Returns documents that contain terms similar to the search term, as measured by a Levenshtein edit distance.

An edit distance is the number of one-character changes needed to turn one term into another. These changes can include:

  • Changing a character (box → fox)
  • Removing a character (black → lack)
  • Inserting a character (sic → sick)
  • Transposing two adjacent characters (act → cat)

To find similar terms, the fuzzy query creates a set of all possible variations, or expansions, of the search term within a specified edit distance. The query then returns exact matches for each expansion.

Example requests

Simple example

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

Example using advanced parameters

GET /_search
{
  "query": {
    "fuzzy": {
      "user.id": {
        "value": "ki",
        "fuzziness": "AUTO",
        "max_expansions": 50,
        "prefix_length": 0,
        "transpositions": true,
        "rewrite": "constant_score"
      }
    }
  }
}

Top-level parameters for fuzzy

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

Parameters for <field>

value
(Required, string) Term you wish to find in the provided <field>.
fuzziness
(Optional, string) Maximum edit distance allowed for matching. See Fuzziness for valid values and more information.
max_expansions

(Optional, integer) Maximum number of variations created. Defaults to 50.

Avoid using a high value in the max_expansions parameter, especially if the prefix_length parameter value is 0. High values in the max_expansions parameter can cause poor performance due to the high number of variations examined.

prefix_length
(Optional, integer) Number of beginning characters left unchanged when creating expansions. Defaults to 0.
transpositions
(Optional, Boolean) Indicates whether edits include transpositions of two adjacent characters (ab → ba). Defaults to true.
rewrite
(Optional, string) Method used to rewrite the query. For valid values and more information, see the rewrite parameter.

Notes

Fuzzy queries will not be executed if search.allow_expensive_queries is set to false.

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