109 lines
2.8 KiB
Plaintext
109 lines
2.8 KiB
Plaintext
[[search-explain]]
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== Explain API
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The explain api computes a score explanation for a query and a specific
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document. This can give useful feedback whether a document matches or
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didn't match a specific query.
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The `index` and `type` parameters expect a single index and a single
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type respectively.
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[float]
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=== Usage
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Full query example:
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[source,js]
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--------------------------------------------------
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curl -XGET 'localhost:9200/twitter/tweet/1/_explain' -d '{
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"query" : {
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"term" : { "message" : "search" }
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}
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}'
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--------------------------------------------------
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This will yield the following result:
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[source,js]
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--------------------------------------------------
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{
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"ok" : true,
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"matches" : true,
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"explanation" : {
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"value" : 0.15342641,
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"description" : "fieldWeight(message:search in 0), product of:",
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"details" : [ {
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"value" : 1.0,
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"description" : "tf(termFreq(message:search)=1)"
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}, {
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"value" : 0.30685282,
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"description" : "idf(docFreq=1, maxDocs=1)"
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}, {
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"value" : 0.5,
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"description" : "fieldNorm(field=message, doc=0)"
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} ]
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}
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}
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--------------------------------------------------
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There is also a simpler way of specifying the query via the `q`
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parameter. The specified `q` parameter value is then parsed as if the
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`query_string` query was used. Example usage of the `q` parameter in the
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explain api:
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[source,js]
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--------------------------------------------------
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curl -XGET 'localhost:9200/twitter/tweet/1/_explain?q=message:search'
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--------------------------------------------------
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This will yield the same result as the previous request.
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[float]
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=== All parameters:
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[horizontal]
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`fields`::
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Allows to control which fields to return as part of the
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document explained (support `_source` for the full document).
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`routing`::
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Controls the routing in the case the routing was used
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during indexing.
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`parent`::
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Same effect as setting the routing parameter.
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`preference`::
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Controls on which shard the explain is executed.
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`source`::
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Allows the data of the request to be put in the query
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string of the url.
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`q`::
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The query string (maps to the query_string query).
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`df`::
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The default field to use when no field prefix is defined within
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the query. Defaults to _all field.
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`analyzer`::
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The analyzer name to be used when analyzing the query
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string. Defaults to the analyzer of the _all field.
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`analyze_wildcard`::
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Should wildcard and prefix queries be analyzed or
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not. Defaults to false.
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`lowercase_expanded_terms`::
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Should terms be automatically lowercased
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or not. Defaults to true.
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`lenient`::
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If set to true will cause format based failures (like
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providing text to a numeric field) to be ignored. Defaults to false.
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`default_operator`::
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The default operator to be used, can be AND or
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OR. Defaults to OR.
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