es - elasticsearch mapping - parameters - normalizer

世界上并没有完美的程序，但是我们并不因此而沮丧，因为写程序就是一个不断追求完美的过程。

问 ：normalizer有什么特点？
答 ：

问 ：normalizer如何使用？
答 ：

# normalizer
PUT /normalizer_test
{
  "settings" : {
    "analysis" : {
      "normalizer" : {
        "my_normalizer" : {
          "type"        : "custom",
          "char_filter" : {},
          "filter"      : ["lowercase", "asciifolding"]
        }
      }
    }
  }, 
  "mappings" : {
    "properties": {
      "name" : {
        "type"       : "keyword",
        "normalizer" : "my_normalizer"
      }
    }
  }
}

# 索引
POST /normalizer_test/_doc/1
{
  "name" : "BÀR"
}

# 索引
POST /normalizer_test/_doc/2
{
  "name" : "bar"
}

# 索引
POST /normalizer_test/_doc/3
{
  "name" : "Bar"
}


# 搜索
GET /normalizer_test/_search
{
  "query" : {
    "term" : {
      "name" : "BAR"
    }
  }
}

# 结果
{
  "took" : 11,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 3,
      "relation" : "eq"
    },
    "max_score" : 0.13353139,
    "hits" : [
      {
        "_index" : "normalizer_test",
        "_type" : "_doc",
        "_id" : "1",
        "_score" : 0.13353139,
        "_source" : {
          "name" : "BÀR"
        }
      },
      {
        "_index" : "normalizer_test",
        "_type" : "_doc",
        "_id" : "2",
        "_score" : 0.13353139,
        "_source" : {
          "name" : "bar"
        }
      },
      {
        "_index" : "normalizer_test",
        "_type" : "_doc",
        "_id" : "3",
        "_score" : 0.13353139,
        "_source" : {
          "name" : "Bar"
        }
      }
    ]
  }
}

# 聚合
GET /normalizer_test/_search
{
  "aggs": {
    "normalizer_aggs" : {
      "terms" : {
        "field" : "name",
        "size"  : 10
      }
    }
  }
}

# 结果
{
  "took" : 11,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 3,
      "relation" : "eq"
    },
    "max_score" : 1.0,
    "hits" : [
      {
        "_index" : "normalizer_test",
        "_type" : "_doc",
        "_id" : "1",
        "_score" : 1.0,
        "_source" : {
          "name" : "BÀR"
        }
      },
      {
        "_index" : "normalizer_test",
        "_type" : "_doc",
        "_id" : "2",
        "_score" : 1.0,
        "_source" : {
          "name" : "bar"
        }
      },
      {
        "_index" : "normalizer_test",
        "_type" : "_doc",
        "_id" : "3",
        "_score" : 1.0,
        "_source" : {
          "name" : "Bar"
        }
      }
    ]
  },
  "aggregations" : {
    "normalizer_aggs" : {
      "doc_count_error_upper_bound" : 0,
      "sum_other_doc_count" : 0,
      "buckets" : [
        {
          "key" : "bar",
          "doc_count" : 3
        }
      ]
    }
  }
}