103 lines
3.3 KiB
Plaintext
103 lines
3.3 KiB
Plaintext
[[query-dsl-match-query-phrase-prefix]]
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=== Match phrase prefix query
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++++
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<titleabbrev>Match phrase prefix</titleabbrev>
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++++
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Returns documents that contain the words of a provided text, in the **same
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order** as provided. The last term of the provided text is treated as a
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<<query-dsl-prefix-query,prefix>>, matching any words that begin with that term.
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[[match-phrase-prefix-query-ex-request]]
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==== Example request
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The following search returns documents that contain phrases beginning with
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`quick brown f` in the `message` field.
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This search would match a `message` value of `quick brown fox` or `two quick
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brown ferrets` but not `the fox is quick and brown`.
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[source,console]
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--------------------------------------------------
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GET /_search
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{
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"query": {
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"match_phrase_prefix": {
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"message": {
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"query": "quick brown f"
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}
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}
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}
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}
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--------------------------------------------------
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[[match-phrase-prefix-top-level-params]]
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==== Top-level parameters for `match_phrase_prefix`
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`<field>`::
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(Required, object) Field you wish to search.
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[[match-phrase-prefix-field-params]]
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==== Parameters for `<field>`
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`query`::
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+
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--
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(Required, string) Text you wish to find in the provided `<field>`.
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The `match_phrase_prefix` query <<analysis,analyzes>> any provided text into
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tokens before performing a search. The last term of this text is treated as a
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<<query-dsl-prefix-query,prefix>>, matching any words that begin with that term.
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--
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`analyzer`::
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(Optional, string) <<analysis,Analyzer>> used to convert text in the `query`
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value into tokens. Defaults to the <<specify-index-time-analyzer,index-time
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analyzer>> mapped for the `<field>`. If no analyzer is mapped, the index's
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default analyzer is used.
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`max_expansions`::
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(Optional, integer) Maximum number of terms to which the last provided term of
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the `query` value will expand. Defaults to `50`.
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`slop`::
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(Optional, integer) Maximum number of positions allowed between matching tokens.
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Defaults to `0`. Transposed terms have a slop of `2`.
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`zero_terms_query`::
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+
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--
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(Optional, string) Indicates whether no documents are returned if the `analyzer`
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removes all tokens, such as when using a `stop` filter. Valid values are:
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`none` (Default)::
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No documents are returned if the `analyzer` removes all tokens.
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`all`::
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Returns all documents, similar to a <<query-dsl-match-all-query,`match_all`>>
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query.
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--
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[[match-phrase-prefix-query-notes]]
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==== Notes
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[[match-phrase-prefix-autocomplete]]
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===== Using the match phrase prefix query for search autocompletion
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While easy to set up, using the `match_phrase_prefix` query for search
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autocompletion can sometimes produce confusing results.
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For example, consider the query string `quick brown f`. This query works by
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creating a phrase query out of `quick` and `brown` (i.e. the term `quick` must
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exist and must be followed by the term `brown`). Then it looks at the sorted
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term dictionary to find the first 50 terms that begin with `f`, and adds these
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terms to the phrase query.
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The problem is that the first 50 terms may not include the term `fox` so the
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phrase `quick brown fox` will not be found. This usually isn't a problem as
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the user will continue to type more letters until the word they are looking
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for appears.
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For better solutions for _search-as-you-type_ see the
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<<completion-suggester,completion suggester>> and
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the <<search-as-you-type,`search_as_you_type` field type>>. |