Elasticsearch how to match documents for which the field tokens are a sub-set of the query tokens

问题

I have a keyword/key-phrase field I tokenize using standard analyser. I want this field to match if if there is a search phrase that has all tokens of this field in it.

For example if the field value is "veni, vidi, vici" and the search phrase is "Ceaser veni,vidi,vici" I want this search phrase to match but search phrase "veni, vidi" not match.

I also need "vidi, veni, vici" (weird!) to match. So the positions and ordering of the terms is not really important. A phrase match would not quite work for me I think.

I can use "bool query" with "minimum_should_match" parameter for this specific example but that is not really what I want as minimum should match is about ratio/number of tokens in the search phrase.

回答1:

Pure ES solution would go like this. You will need two requests.

1) First you need to pass user query through analyze api to get all the search tokens.

curl -XGET 'localhost:9200/_analyze' -d '
{
  "analyzer" : "standard",
  "text" : "Ceaser veni,vidi,vici"
}'

you will get 4 tokens ceaser, veni, vidi, vici . You need to pass these tokens as an array to next search request.

2) We need to search for documents whose tokens are subset of search tokens.

{
  "query": {
    "filtered": {
      "filter": {
        "bool": {
          "must": [
            {
              "query": {
                "match": {
                  "title": "Ceaser veni,vidi,vici"
                }
              }
            },
            {
              "script": {
                "script": "if(search_tokens.containsAll(doc['title'].values)){return true;}",
                "params": {
                  "search_tokens": [
                    "ceaser",
                    "veni",
                    "vidi",
                    "vici"
                  ]
                }
              }
            }
          ]
        }
      }
    }
  }
}

Here job of first match query inside the filter is to narrow down the documents on which script should run. containsAll method will check if the documents tokens are sublist of search tokens. This will be slow but will do the job with your current set up. One big improvement you can do is store tokens as an array so that doc['title'].values can be replaced with that field which will improve the script.

Hope this helps!

回答2:

No built-in solution but this works:

Add an extra field with the number of terms in the field for each document. So in your "veni, vidi, vici" example, you would have a field like "field_term_count" : 3.
Perform a separate match search for each token in the search query.
Sum the number of searches that matched for each document with at least one match (e.g. a hashtable with key of document ID and value of count).
Compare the number of matches in 3 to the "field_term_count" field for each of the documents with matches. If they are equal then the document is a match.

Then "Ceaser veni,vidi,vici" will match but the search phrases "veni, vidi" will not, as desired. It should be quite fast for reasonable numbers of matches.

来源：https://stackoverflow.com/questions/35082284/elasticsearch-how-to-match-documents-for-which-the-field-tokens-are-a-sub-set-of

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