Multi-fields Reindex

1. 先获取索引

get http://192.168.1.51:9200/xxd/_mapping/p1  

得到一个JSON，修改这个JSON

官方文档地址：
https://www.elastic.co/guide/en/elasticsearch/reference/current/indices-get-mapping.html

2. 修改索引

官网的例子：

PUT my_index
{
  "mappings": {
    "my_type": {
      "properties": {
        "city": {
          "type": "text",
          "fields": {
            "raw": { 
              "type":  "keyword"
            }
          }
        }
      }
    }
  }
}

如果直接照上面的改会报错：no handler for type [keyword] declared on field [raw]
keyword是ES 5中的一个新类型，ES 2.X不支持
这里实际上修改为：

 "currentCompany": {
    "type": "string",
    "fields": {
      "raw": {
        "type": "string",
        "index": "not_analyzed"
      }
    }
  },
  
"headline": {
    "type": "string",
    "fields": {
      "raw": {
        "type": "string",
        "index": "not_analyzed"
      }
    }
  },
  
"industry": {
    "type": "string",
    "fields": {
      "raw": {
        "type": "string",
        "index": "not_analyzed"
      }
    }
  },
  
  "location": {
    "type": "string",
    "fields": {
      "raw": {
        "type": "string",
        "index": "not_analyzed"
      }
    }
  },

删掉第一级别的==xxd== ，保留如下：

{
  "mappings": {
    "p1": {
    ......

3. 添加新的类型到索引中

根据上面修改的JSON创建一个新的类型

put http://192.168.1.51:9200/xxd2
{
  "mappings": {
    "p1": {
      "properties": {
      ......

官方文档地址：
https://www.elastic.co/guide/en/elasticsearch/reference/current/indices-put-mapping.html

4. 通过get验证新创建的索引

get http://192.168.1.51:9200/xxd2/_mapping/p1  

5. Reindex API

官网地址：
https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-reindex.html#docs-reindex
reindex API是新的，应该仍然被认为是实验性的。 API可能以不向后兼容的方式更改。
重建索引不会尝试设置目标索引。它不复制源索引的设置。您应该在运行_reindex操作之前设置目标索引，包括设置映射，分片计数，副本等。

POST http://192.168.1.51:9200/_reindex
{
  "source": {
    "index": "xxd"
  },
  "dest": {
    "index": "xxd2"
  }
}

6. 测试

POST http://192.168.1.51:9200/xxd2/p1/_search?search_type=count 
{
  "aggs": {
    "colors": {
      "terms": {
        "field": "location.raw"
      }
    }
  }
}