文檔是不可改變的，不能修改他們。
如果想要更新現(xiàn)在有的文檔，需要重建索引或者進(jìn)行替換
不能訪問舊版本的文檔，但它不是立即刪除的

PUT /website/blog/123
{
  "title": "My first blog entry",
  "text":  "I am starting to get the hang of this...",
  "date":  "2014/01/02"
}

返回的結(jié)果：_version自增，created，表示不是create

{
  "_index" :   "website",
  "_type" :    "blog",
  "_id" :      "123",
  "_version" : 2,
  "created":   false
}

可以利用_version來保證安全

put請求，（1）是指_version在1的時候才能更新

PUT /website/blog/1?version=1 (1)
{
  "title": "My first blog entry",
  "text":  "Starting to get the hang of this..."
}

更新成功

{
  "_index":   "website",
  "_type":    "blog",
  "_id":      "1",
  "_version": 2
  "created":  false
}

再次相同請求，則```490 Conflict

{
   "error": {
      "root_cause": [
         {
            "type": "version_conflict_engine_exception",
            "reason": "[blog][1]: version conflict, current [2], provided [1]",
            "index": "website",
            "shard": "3"
         }
      ],
      "type": "version_conflict_engine_exception",
      "reason": "[blog][1]: version conflict, current [2], provided [1]",
      "index": "website",
      "shard": "3"
   },
   "status": 409
}

外部系統(tǒng)保證安全

指定版本號需要大于ES當(dāng)前版本號
創(chuàng)建外部版本號為5的博客

PUT /website/blog/2?version=5&version_type=external
{
  "title": "My first external blog entry",
  "text":  "Starting to get the hang of this..."
}

成功響應(yīng)：

{
  "_index":   "website",
  "_type":    "blog",
  "_id":      "2",
  "_version": 5,
  "created":  true
}

更新這個文檔，指定新版本號

PUT /website/blog/2?version=10&version_type=external
{
  "title": "My first external blog entry",
  "text":  "This is a piece of cake..."
}

成功，失敗則返回之前的沖突錯誤

{
  "_index":   "website",
  "_type":    "blog",
  "_id":      "2",
  "_version": 10,
  "created":  false
}