Query String Queryedit

A query that uses a query parser in order to parse its content. Here is an example:

{
    "query_string" : {
        "default_field" : "content",
        "query" : "this AND that OR thus"
    }
}

The query_string top level parameters include:

Parameter Description

query

The actual query to be parsed. See Query string syntax.

default_field

The default field for query terms if no prefix field is specified. Defaults to the index.query.default_field index settings, which in turn defaults to _all.

default_operator

The default operator used if no explicit operator is specified. For example, with a default operator of OR, the query capital of Hungary is translated to capital OR of OR Hungary, and with default operator of AND, the same query is translated to capital AND of AND Hungary. The default value is OR.

analyzer

The analyzer name used to analyze the query string.

allow_leading_wildcard

When set, * or ? are allowed as the first character. Defaults to true.

lowercase_expanded_terms

Whether terms of wildcard, prefix, fuzzy, and range queries are to be automatically lower-cased or not (since they are not analyzed). Default it true.

enable_position_increments

Set to true to enable position increments in result queries. Defaults to true.

fuzzy_max_expansions

Controls the number of terms fuzzy queries will expand to. Defaults to 50

fuzziness

Set the fuzziness for fuzzy queries. Defaults to AUTO. See the section called “Fuzzinessedit” for allowed settings.

fuzzy_prefix_length

Set the prefix length for fuzzy queries. Default is 0.

phrase_slop

Sets the default slop for phrases. If zero, then exact phrase matches are required. Default value is 0.

boost

Sets the boost value of the query. Defaults to 1.0.

analyze_wildcard

By default, wildcards terms in a query string are not analyzed. By setting this value to true, a best effort will be made to analyze those as well.

auto_generate_phrase_queries

Defaults to false.

max_determinized_states

Limit on how many automaton states regexp queries are allowed to create. This protects against too-difficult (e.g. exponentially hard) regexps. Defaults to 10000.

minimum_should_match

A value controlling how many "should" clauses in the resulting boolean query should match. It can be an absolute value (2), a percentage (30%) or a combination of both.

lenient

If set to true will cause format based failures (like providing text to a numeric field) to be ignored.

locale

Locale that should be used for string conversions. Defaults to ROOT.

time_zone

Time Zone to be applied to any range query related to dates. See also JODA timezone.

When a multi term query is being generated, one can control how it gets rewritten using the rewrite parameter.

Default Fieldedit

When not explicitly specifying the field to search on in the query string syntax, the index.query.default_field will be used to derive which field to search on. It defaults to _all field.

So, if _all field is disabled, it might make sense to change it to set a different default field.

Multi Fieldedit

The query_string query can also run against multiple fields. Fields can be provided via the "fields" parameter (example below).

The idea of running the query_string query against multiple fields is to expand each query term to an OR clause like this:

field1:query_term OR field2:query_term | ...

For example, the following query

{
    "query_string" : {
        "fields" : ["content", "name"],
        "query" : "this AND that"
    }
}

matches the same words as

{
    "query_string": {
      "query": "(content:this OR name:this) AND (content:that OR name:that)"
    }
}

Since several queries are generated from the individual search terms, combining them can be automatically done using either a dis_max query or a simple bool query. For example (the name is boosted by 5 using ^5 notation):

{
    "query_string" : {
        "fields" : ["content", "name^5"],
        "query" : "this AND that OR thus",
        "use_dis_max" : true
    }
}

Simple wildcard can also be used to search "within" specific inner elements of the document. For example, if we have a city object with several fields (or inner object with fields) in it, we can automatically search on all "city" fields:

{
    "query_string" : {
        "fields" : ["city.*"],
        "query" : "this AND that OR thus",
        "use_dis_max" : true
    }
}

Another option is to provide the wildcard fields search in the query string itself (properly escaping the * sign), for example: city.\*:something.

When running the query_string query against multiple fields, the following additional parameters are allowed:

Parameter Description

use_dis_max

Should the queries be combined using dis_max (set it to true), or a bool query (set it to false). Defaults to true.

tie_breaker

When using dis_max, the disjunction max tie breaker. Defaults to 0.

The fields parameter can also include pattern based field names, allowing to automatically expand to the relevant fields (dynamically introduced fields included). For example:

{
    "query_string" : {
        "fields" : ["content", "name.*^5"],
        "query" : "this AND that OR thus",
        "use_dis_max" : true
    }
}

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