索引别名像一个快捷方式或者软连接:
在运行的集群中可以直接无缝切换。
给多个索引分组
给索引的一个子集创建视图

基本用法:

创建名为my_index_v1的索引,将别名my_index指向它

curl -X PUT “localhost:9200/my_index_v1”
curl -X PUT “localhost:9200/my_index_v1/_alias/my_index”

检查这个别名指向了哪一个索引:

curl -X GET “localhost:9200/*/_alias/my_index”

{"my_index_v1":{"aliases":{"my_index":{}}}}

哪些别名指向了这个索引:

curl -X GET “localhost:9200/my_index_v1/_alias/*”

利用索引别名修改映射:

curl -X PUT "localhost:9200/my_index_v2" -H 'Content-Type: application/json' -d'
{
  "mappings": {
      "my_type": {
          "properties": {
              "tags": {
                  "type":   "string",
                  "index":  "not_analyzed"
              }
          }
      }
  }
}'

使用reindex的方式重新索引数据。scroll导出数据,bulk导入新的索引。

Scroll API查出第一波数据及获取_scroll游标,去掉sort字段可以加快排序速度.

curl -XGET 'localhost:9200/my_index_v1/_search?scroll=3m' -H 'Content-Type: application/json' -d'
{
  "query":{
      "match_all": {}
  },
  "sort": ["_doc"],
  "size": 2000
}

{"_scroll_id":"DnF1ZXJ5VGhlbkZldGNoBQAAAAAAAABPFnEwNDBMUERrUW1HZlpEZVJCRkxzRGcAAAAAAAAAUBZxMDQwTFBEa1FtR2ZaRGVSQkZMc0RnAAAAAAAAAE0WcTA0MExQRGtRbUdmWkRlUkJGTHNEZwAAAAAAAABMFnEwNDBMUERrUW1HZlpEZVJCRkxzRGcAAAAAAAAAThZxMDQwTFBEa1FtR2ZaRGVSQkZMc0Rn","took":84,"timed_out":false,"_shards":{"total":5,"successful":5,"failed":0},"hits":{"total":0,"max_score":null,"hits":[]}}

根据返回的_scroll_id继续向下获取数据,直到结束

curl -XGET  'localhost:9200/_search/scroll'  -d'
{
  "scroll" : "30m", 
  "scroll_id" : "DnF1ZXJ5VGhlbkZldGNoBQAAAAAAAABPFnEwNDBMUERrUW1HZlpEZVJCRkxzRGcAAAAAAAAAUBZxMDQwTFBEa1FtR2ZaRGVSQkZMc0RnAAAAAAAAAE0WcTA0MExQRGtRbUdmWkRlUkJGTHNEZwAAAAAAAABMFnEwNDBMUERrUW1HZlpEZVJCRkxzRGcAAAAAAAAAThZxMDQwTFBEa1FtR2ZaRGVSQkZMc0Rn" 
}'

使用bulk API插入数据

curl -XPOST 'localhost:9200/my_index_v2/_bulk' -H 'Content-Type: application/json' -d'
{"index": {"_index" : "my_index_new", "_type" : "my_type", "_id" : "3"}}
{"title" : "2017-01-01"}'

使用原子操作将索引别名指向新的索引。


curl -X POST “localhost:9200/_aliases” -H ‘Content-Type: application/json’ -d’
{
  “actions”: [

{ "remove": { "index": "my_index_v1", "alias": "my_index" }},
{ "add":    { "index": "my_index_v2", "alias": "my_index" }}

]
}’