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Prefix query

Use the prefix query to search for terms that begin with a specific prefix. For example, the following query searches for documents in which the speaker field contains a term that starts with KING H:

  1. GET shakespeare/_search
  2. {
  3.   "query": {
  4.     "prefix": {
  5.       "speaker": "KING H"
  6.     }
  7.   }
  8. }

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To provide parameters, you can use a query equivalent to the preceding one with the following extended syntax:

  1. GET shakespeare/_search
  2. {
  3.   "query": {
  4.     "prefix": {
  5.       "speaker": {
  6.         "value": "KING H"
  7.       }
  8.     }
  9.   }
  10. }

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Parameters

The query accepts the name of the field (<field>) as a top-level parameter:

  1. GET _search
  2. {
  3.   "query": {
  4.     "prefix": {
  5.       "<field>": {
  6.         "value": "sample",
  7.         ... 
  8.       }
  9.     }
  10.   }
  11. }

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The <field> accepts the following parameters. All parameters except value are optional.

ParameterData typeDescription
valueStringThe term to search for in the field specified in <field>.
case_insensitiveBooleanIf true, allows case-insensitive matching of the value with the indexed field values. Default is false (case sensitivity is determined by the field’s mapping).
rewriteStringDetermines how OpenSearch rewrites and scores multi-term queries. Valid values are constant_score, scoring_boolean, constant_score_boolean, top_terms_N, top_terms_boost_N, and top_terms_blended_freqs_N. Default is constant_score.

If search.allow_expensive_queries is set to false, prefix queries are not run. If index_prefixes is enabled, the search.allow_expensive_queries setting is ignored and an optimized query is built and run.