Fuzzy query

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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

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Simple example

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

Example using advanced parameters

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

Top-level parameters for fuzzy

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

Parameters for <field>

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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.