"length" : 10
        },
        "truncate20_filter" : {
          "type" : "truncate",
          "length" : 20
        },
        "alphanum_word_filter" : {
          "type" : "alphanum_word",
          "max_token_length" : 20
        },
        "minhash_filter" : {
          "type" : "minhash",
          "seed" : 1,
          "bit" : 2,
          "size" : 64
        },