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b676583ba5
With this commit we deprecate the widely misunderstood fuzzy query but will still allow the fuzziness parameter in match queries and suggesters. Relates to #15760
104 lines
2.6 KiB
Plaintext
104 lines
2.6 KiB
Plaintext
[[query-dsl-fuzzy-query]]
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=== Fuzzy Query
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deprecated[3.0.0, Will be removed without a replacement for `string` fields. Note that the `fuzziness` parameter is still supported for match queries and in suggesters. Use range queries for `date` and `numeric` fields instead.]
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The fuzzy query uses similarity based on Levenshtein edit distance for
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`string` fields, and a `+/-` margin on numeric and date fields.
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==== String fields
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The `fuzzy` query generates all possible matching terms that are within the
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maximum edit distance specified in `fuzziness` and then checks the term
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dictionary to find out which of those generated terms actually exist in the
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index.
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Here is a simple example:
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[source,js]
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--------------------------------------------------
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{
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"fuzzy" : { "user" : "ki" }
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}
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--------------------------------------------------
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Or with more advanced settings:
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[source,js]
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--------------------------------------------------
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{
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"fuzzy" : {
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"user" : {
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"value" : "ki",
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"boost" : 1.0,
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"fuzziness" : 2,
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"prefix_length" : 0,
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"max_expansions": 100
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}
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}
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}
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--------------------------------------------------
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[float]
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===== Parameters
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[horizontal]
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`fuzziness`::
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The maximum edit distance. Defaults to `AUTO`. See <<fuzziness>>.
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`prefix_length`::
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The number of initial characters which will not be ``fuzzified''. This
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helps to reduce the number of terms which must be examined. Defaults
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to `0`.
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`max_expansions`::
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The maximum number of terms that the `fuzzy` query will expand to.
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Defaults to `50`.
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WARNING: This query can be very heavy if `prefix_length` is set to `0` and if
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`max_expansions` is set to a high number. It could result in every term in the
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index being examined!
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[float]
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==== Numeric and date fields
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Performs a <<query-dsl-range-query>> ``around'' the value using the
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`fuzziness` value as a `+/-` range, where:
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-fuzziness <= field value <= +fuzziness
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For example:
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[source,js]
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--------------------------------------------------
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{
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"fuzzy" : {
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"price" : {
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"value" : 12,
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"fuzziness" : 2
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}
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}
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}
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--------------------------------------------------
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Will result in a range query between 10 and 14. Date fields support
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<<time-units,time values>>, eg:
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[source,js]
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--------------------------------------------------
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{
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"fuzzy" : {
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"created" : {
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"value" : "2010-02-05T12:05:07",
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"fuzziness" : "1d"
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}
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}
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}
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--------------------------------------------------
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See <<fuzziness>> for more details about accepted values.
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