Field stats APIedit
This functionality is experimental and may be changed or removed completely in a future release.
The field stats api allows one to find statistical properties of a field without executing a search, but looking up measurements that are natively available in the Lucene index. This can be useful to explore a dataset which you don’t know much about. For example, this allows creating a histogram aggregation with meaningful intervals based on the min/max range of values.
The field stats api by defaults executes on all indices, but can execute on specific indices too.
All indices:
curl -XGET "http://localhost:9200/_field_stats?fields=rating"
Specific indices:
curl -XGET "http://localhost:9200/index1,index2/_field_stats?fields=rating"
Supported request options:
|
|
A list of fields to compute stats for. |
|
|
Defines if field stats should be returned on a per index level or on a
cluster wide level. Valid values are |
Field statisticsedit
The field stats api is supported on string based, number based and date based fields and can return the following statistics per field:
|
|
The total number of documents. |
|
|
The number of documents that have at least one term for this field, or -1 if this measurement isn’t available on one or more shards. |
|
|
The percentage of documents that have at least one value for this field. This
is a derived statistic and is based on the |
|
|
The sum of each term’s document frequency in this field, or -1 if this measurement isn’t available on one or more shards. Document frequency is the number of documents containing a particular term. |
|
|
The sum of the term frequencies of all terms in this field across all documents, or -1 if this measurement isn’t available on one or more shards. Term frequency is the total number of occurrences of a term in a particular document and field. |
|
|
The lowest value in the field represented in a displayable form. |
|
|
The highest value in the field represented in a displayable form. |
Documents marked as deleted (but not yet removed by the merge process) still affect all the mentioned statistics.
Example 1. Cluster level field statistics
GET /_field_stats?fields=rating,answer_count,creation_date,display_name
{
"_shards": {
"total": 1,
"successful": 1,
"failed": 0
},
"indices": {
"_all": { 
"fields": {
"creation_date": {
"max_doc": 1326564,
"doc_count": 564633,
"density": 42,
"sum_doc_freq": 2258532,
"sum_total_term_freq": -1,
"min_value": "2008-08-01T16:37:51.513Z",
"max_value": "2013-06-02T03:23:11.593Z"
},
"display_name": {
"max_doc": 1326564,
"doc_count": 126741,
"density": 9,
"sum_doc_freq": 166535,
"sum_total_term_freq": 166616,
"min_value": "0",
"max_value": "정혜선"
},
"answer_count": {
"max_doc": 1326564,
"doc_count": 139885,
"density": 10,
"sum_doc_freq": 559540,
"sum_total_term_freq": -1,
"min_value": 0,
"max_value": 160
},
"rating": {
"max_doc": 1326564,
"doc_count": 437892,
"density": 33,
"sum_doc_freq": 1751568,
"sum_total_term_freq": -1,
"min_value": -14,
"max_value": 1277
}
}
}
}
}
|
The |
Example 2. Indices level field statistics
GET /_field_stats?fields=rating,answer_count,creation_date,display_name&level=indices
{
"_shards": {
"total": 1,
"successful": 1,
"failed": 0
},
"indices": {
"stack": {
"fields": {
"creation_date": {
"max_doc": 1326564,
"doc_count": 564633,
"density": 42,
"sum_doc_freq": 2258532,
"sum_total_term_freq": -1,
"min_value": "2008-08-01T16:37:51.513Z",
"max_value": "2013-06-02T03:23:11.593Z"
},
"display_name": {
"max_doc": 1326564,
"doc_count": 126741,
"density": 9,
"sum_doc_freq": 166535,
"sum_total_term_freq": 166616,
"min_value": "0",
"max_value": "정혜선"
},
"answer_count": {
"max_doc": 1326564,
"doc_count": 139885,
"density": 10,
"sum_doc_freq": 559540,
"sum_total_term_freq": -1,
"min_value": 0,
"max_value": 160
},
"rating": {
"max_doc": 1326564,
"doc_count": 437892,
"density": 33,
"sum_doc_freq": 1751568,
"sum_total_term_freq": -1,
"min_value": -14,
"max_value": 1277
}
}
}
}
}
|
The |