问题
In Solr I can use the query
function query to return a numerical score for a query and I can user that in the context of a bf
parameter something like bf=product(query('cat'),query('dog'))
to multiply two relevance scores together.
Elasticsearch has search API that is generally more flexible to work with, but I can't figure out how I would accomplish the same feat. I can use _score
in a script_function of a function_query but I can only user the _score
of the main query. How can I incorporate the score of another query? How can I multiply the scores together?
回答1:
You could script a TF*IDF scoring function using a function_score
query. Something like this (ignoring Lucene's query and length normalization):
"script": "tf = _index[field][term].tf(); idf = (1 + log ( _index.numDocs() / (_index[field][term].df() + 1))); return sqrt(tf) * pow(idf,2)"
You'd take the product of those function results for 'cat' and 'dog' and add them to your original query score.
Here's the full query gist.
回答2:
Alternately, if you've got something in that bf
that's heavyweight enough you'd rather not run it across the entire set of matches, you could use rescore requests to modify the score of the top N ranked ORIGINAL QUERY
results using subsequent scoring passes with your (cat, dog, etc...) scoring-queries.
来源:https://stackoverflow.com/questions/31755642/how-can-i-multiply-the-score-of-two-queries-together-in-elasticsearch