matching two string arrays in elasticsearch

You need to add different should clause in order percentage attribute to work, adding below sample example similar to what you have to show:

Index mapping

{
    "mappings": {
        "properties": {
            "tags": {
                "type": "text"
            }
        }
    }
}

Index sample doc

{
  "tags" : ["tag1", "tag2", "tag3", "tag4", "tag5"]
}

search query which has more than 50% matching tag returning doc

{
  "query": {
    "bool" : {
      "should" : [
        { "term" : { "tags" : "tag1" } },
        { "term" : { "tags" : "tag2" } },
        { "term" : { "tags" : "tag3" } },
        { "term" : { "tags" : "tag8" } }
      ],
      "minimum_should_match" : "50%",
      "boost" : 1.0
    }
  }
}  

Search result

"hits": [
      {
        "_index": "tags",
        "_type": "_doc",
        "_id": "1",
        "_score": 1.0,
        "_source": {
          "tags": [
            "tag1",
            "tag2",
            "tag3",
            "tag4",
            "tag5"
          ]
        }
      }

Sample where it won't bring search result for 50%

{
  "query": {
    "bool" : {
      "should" : [
        { "term" : { "tags" : "tag1" } },
        { "term" : { "tags" : "tag6" } },
        { "term" : { "tags" : "tag7" } },
        { "term" : { "tags" : "tag8" } }
      ],
      "minimum_should_match" : "50%",
      "boost" : 1.0
    }
  }
}