80 lines
2.4 KiB
Plaintext
80 lines
2.4 KiB
Plaintext
[[query-dsl-regexp-query]]
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== Regexp Query
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The `regexp` query allows you to use regular expression term queries.
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See <<regexp-syntax>> for details of the supported regular expression language.
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The "term queries" in that first sentence means that Elasticsearch will apply
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the regexp to the terms produced by the tokenizer for that field, and not
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to the original text of the field.
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*Note*: The performance of a `regexp` query heavily depends on the
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regular expression chosen. Matching everything like `.*` is very slow as
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well as using lookaround regular expressions. If possible, you should
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try to use a long prefix before your regular expression starts. Wildcard
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matchers like `.*?+` will mostly lower performance.
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[source,js]
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--------------------------------------------------
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{
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"regexp":{
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"name.first": "s.*y"
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}
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}
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--------------------------------------------------
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Boosting is also supported
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[source,js]
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--------------------------------------------------
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{
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"regexp":{
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"name.first":{
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"value":"s.*y",
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"boost":1.2
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}
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}
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}
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--------------------------------------------------
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You can also use special flags
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[source,js]
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--------------------------------------------------
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{
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"regexp":{
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"name.first": {
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"value": "s.*y",
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"flags" : "INTERSECTION|COMPLEMENT|EMPTY"
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}
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}
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}
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--------------------------------------------------
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Possible flags are `ALL` (default), `ANYSTRING`, `COMPLEMENT`,
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`EMPTY`, `INTERSECTION`, `INTERVAL`, or `NONE`. Please check the
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http://lucene.apache.org/core/4_9_0/core/org/apache/lucene/util/automaton/RegExp.html[Lucene
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documentation] for their meaning
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Regular expressions are dangerous because it's easy to accidentally
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create an innocuous looking one that requires an exponential number of
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internal determinized automaton states (and corresponding RAM and CPU)
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for Lucene to execute. Lucene prevents these using the
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`max_determinized_states` setting (defaults to 10000). You can raise
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this limit to allow more complex regular expressions to execute.
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[source,js]
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--------------------------------------------------
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{
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"regexp":{
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"name.first": {
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"value": "s.*y",
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"flags" : "INTERSECTION|COMPLEMENT|EMPTY",
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"max_determinized_states": 20000
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}
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}
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}
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--------------------------------------------------
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include::regexp-syntax.asciidoc[]
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