Match Query

fuzziness allows fuzzy matching based on the type of field being queried. See Fuzziness for allowed settings.

The prefix_length and max_expansions can be set in this case to control the fuzzy process. If the fuzzy option is set the query will use top_terms_blended_freqs_${max_expansions} as its rewrite method the fuzzy_rewrite parameter allows to control how the query will get rewritten.

Fuzzy transpositions (ab → ba) are allowed by default but can be disabled by setting fuzzy_transpositions to false.

Note that fuzzy matching is not applied to terms with synonyms, as under the hood these terms are expanded to a special synonym query that blends term frequencies, which does not support fuzzy expansion.

GET /_search
{
    "query": {
        "match" : {
            "message" : {
                "query" : "this is a test",
                "operator" : "and"
            }
        }
    }
}

If the analyzer used removes all tokens in a query like a stop filter does, the default behavior is to match no documents at all. In order to change that the zero_terms_query option can be used, which accepts none (default) and all which corresponds to a match_all query.

GET /_search
{
    "query": {
        "match" : {
            "message" : {
                "query" : "to be or not to be",
                "operator" : "and",
                "zero_terms_query": "all"
            }
        }
    }
}

The match query supports a cutoff_frequency that allows specifying an absolute or relative document frequency where high frequency terms are moved into an optional subquery and are only scored if one of the low frequency (below the cutoff) terms in the case of an or operator or all of the low frequency terms in the case of an and operator match.

This query allows handling stopwords dynamically at runtime, is domain independent and doesn’t require a stopword file. It prevents scoring / iterating high frequency terms and only takes the terms into account if a more significant / lower frequency term matches a document. Yet, if all of the query terms are above the given cutoff_frequency the query is automatically transformed into a pure conjunction (and) query to ensure fast execution.

The cutoff_frequency can either be relative to the total number of documents if in the range [0..1) or absolute if greater or equal to 1.0.

Here is an example showing a query composed of stopwords exclusively:

GET /_search
{
    "query": {
        "match" : {
            "message" : {
                "query" : "to be or not to be",
                "cutoff_frequency" : 0.001
            }
        }
    }
}

The match query supports multi-terms synonym expansion with the synonym_graph token filter. When this filter is used, the parser creates a phrase query for each multi-terms synonyms. For example, the following synonym: "ny, new york" would produce:

(ny OR ("new york"))

It is also possible to match multi terms synonyms with conjunctions instead:

GET /_search
{
   "query": {
       "match" : {
           "message": {
               "query" : "ny city",
               "auto_generate_synonyms_phrase_query" : false
           }
       }
   }
}

The example above creates a boolean query:

(ny OR (new AND york)) city)

that matches documents with the term ny or the conjunction new AND york. By default the parameter auto_generate_synonyms_phrase_query is set to true.