Rank feature datatypeedit
A rank_feature field can index numbers so that they can later be used to boost
documents in queries with a rank_feature query.
PUT my_index
{
"mappings": {
"properties": {
"pagerank": {
"type": "rank_feature"
},
"url_length": {
"type": "rank_feature",
"positive_score_impact": false
}
}
}
}
PUT my_index/_doc/1
{
"pagerank": 8,
"url_length": 22
}
GET my_index/_search
{
"query": {
"rank_feature": {
"field": "pagerank"
}
}
}
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Rank feature fields must use the |
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Rank features that correlate negatively with the score need to declare it |
rank_feature fields only support single-valued fields and strictly positive
values. Multi-valued fields and negative values will be rejected.
rank_feature fields do not support querying, sorting or aggregating. They may
only be used within rank_feature queries.
rank_feature fields only preserve 9 significant bits for the precision, which
translates to a relative error of about 0.4%.
Rank features that correlate negatively with the score should set
positive_score_impact to false (defaults to true). This will be used by
the rank_feature query to modify the scoring formula
in such a way that the score decreases with the value of the feature instead of
increasing. For instance in web search, the url length is a commonly used
feature which correlates negatively with scores.