elasticsearch数据迁移到新索引（5.5.3

无法随意更改索引中字段类型(一旦设置了映射规则之后就不能修改了，因为lucene实现的倒排索引生成后不允许修改)，只能给索引加新字段，或者重建索引。

以下为重建索引流程，只应用于小数据迁移

1.建新索引

PUT /index_record_v1

2.查旧索引mapping

GET /index_record/_mapping/type_record

3.设置新索引mapping

POST /index_record_v1/type_record/_mapping
{
  "properties": {
          "id": {
            "type": "keyword"
          },
          "name": {
            "type": "keyword"
          },
          "value": {
            "type": "double"
          }
   }
}

4.原索引数据拷贝到新索引下

POST _reindex
{
  "source": {"index": "index_record"},
  "dest": {"index": "index_record_v1"}
}

5.删除原索引

DELETE /index_record

6.新索引起别名

POST _aliases
{
	"actions": [
					{
						"add": {
						"index": "index_record_v1",
						"alias": "index_record"
						}
					}
				]
}