Explain API
editExplain API
editThe explain api computes a score explanation for a query and a specific document. This can give useful feedback whether a document matches or didn’t match a specific query.
Note that a single index must be provided to the index
parameter.
Usage
editFull query example:
GET /twitter/_doc/0/_explain { "query" : { "match" : { "message" : "elasticsearch" } } }
This will yield the following result:
{ "_index": "twitter", "_type": "_doc", "_id": "0", "matched": true, "explanation": { "value": 1.6943599, "description": "weight(message:elasticsearch in 0) [PerFieldSimilarity], result of:", "details": [ { "value": 1.6943599, "description": "score(doc=0,freq=1.0 = termFreq=1.0\n), product of:", "details": [ { "value": 1.3862944, "description": "idf, computed as log(1 + (docCount - docFreq + 0.5) / (docFreq + 0.5)) from:", "details": [ { "value": 1.0, "description": "docFreq", "details": [] }, { "value": 5.0, "description": "docCount", "details": [] } ] }, { "value": 1.2222223, "description": "tfNorm, computed as (freq * (k1 + 1)) / (freq + k1 * (1 - b + b * fieldLength / avgFieldLength)) from:", "details": [ { "value": 1.0, "description": "termFreq=1.0", "details": [] }, { "value": 1.2, "description": "parameter k1", "details": [] }, { "value": 0.75, "description": "parameter b", "details": [] }, { "value": 5.4, "description": "avgFieldLength", "details": [] }, { "value": 3.0, "description": "fieldLength", "details": [] } ] } ] } ] } }
There is also a simpler way of specifying the query via the q
parameter. The specified q
parameter value is then parsed as if the
query_string
query was used. Example usage of the q
parameter in the
explain api:
GET /twitter/_doc/0/_explain?q=message:search
This will yield the same result as the previous request.
All parameters:
edit
|
Set to |
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Allows to control which stored fields to return as part of the document explained. |
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Controls the routing in the case the routing was used during indexing. |
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Same effect as setting the routing parameter. |
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Controls on which shard the explain is executed. |
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Allows the data of the request to be put in the query string of the url. |
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The query string (maps to the query_string query). |
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The default field to use when no field prefix is defined within the query. Defaults to _all field. |
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The analyzer name to be used when analyzing the query string. Defaults to the analyzer of the _all field. |
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Should wildcard and prefix queries be analyzed or not. Defaults to false. |
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If set to true will cause format based failures (like providing text to a numeric field) to be ignored. Defaults to false. |
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The default operator to be used, can be AND or OR. Defaults to OR. |