Elasticsearch之CURL命令的version控制

 

 

　　普通關系型數據庫使用的是（悲觀並發控制（PCC））

　　　　當我們在修改一個數據前先鎖定這一行，然后確保只有讀取到數據的這個線程可以修改這一行數據

　　

　　ES使用的是（樂觀並發控制（OCC））　　

　　　　ES不會阻止某一數據的訪問，然而，如果基礎數據在我們讀取和寫入的間隔中發生了變化，更新就會失敗，這時候就由程序來決定如何處理這個沖突。它可以重新讀取新數據來進行更新，又或者將這一情況直接反饋給用戶。

　　ES如何實現版本控制（使用es內部版本號）

　　　　1）首先得到想要修改的文檔，獲取版本version號

curl -XGET http://master:9200/zhouls/user/2

[hadoop@master elasticsearch-2.4.0]$ curl -XGET http://master:9200/zhouls/user/2
{"_index":"zhouls","_type":"user","_id":"2","_version":1,"found":true,"_source":{"name" : "john"  , "age" : 28}}[hadoop@master elasticsearch-2.4.0]$ 
[hadoop@master elasticsearch-2.4.0]$ 
[hadoop@master elasticsearch-2.4.0]$ 

 

 

 

 

 

 

 

 

 

 

　　　　2）在執行更新操作的時候把版本號傳過去

curl -XPUT http://master:9200/zhouls/user/2?version=1  -d  '{"name" : "john1" , "age" : 29}'

 

[hadoop@master elasticsearch-2.4.0]$ curl -XPUT http://master:9200/zhouls/user/2?version=1  -d  '{"name" : "john1" , "age" : 29}'
{"_index":"zhouls","_type":"user","_id":"2","_version":2,"_shards":{"total":2,"successful":2,"failed":0},"created":false}[hadoop@master elasticsearch-2.4.0]$ 

 

 

 

 

 

 

 

 

 

 

 

 

curl -XPOST http://master:9200/zhouls/user/2/_update?version=2  -d  '{"doc" :{"age" : 30}}'

 

[hadoop@master elasticsearch-2.4.0]$ curl -XPOST http://master:9200/zhouls/user/2/_update?version=2  -d  '{"doc" :{"age" : 30}}'
{"_index":"zhouls","_type":"user","_id":"2","_version":3,"_shards":{"total":2,"successful":2,"failed":0}}[hadoop@master elasticsearch-2.4.0]$ 
[hadoop@master elasticsearch-2.4.0]$ 

 

 

 

 

 

 

 

 

 

 

 

 　　

 

 

 

 

 　　3）如果傳遞的版本號和待更新的文檔的版本號不一致，則會更新失敗。

　　現在，待更新文檔的版本號是3。我分別傳1和穿4進入，都會報更新失敗。如下

[hadoop@master elasticsearch-2.4.0]$ curl -XPOST http://master:9200/zhouls/user/2/_update?version=2  -d  '{"doc" :{"age" : 30}}'
{"_index":"zhouls","_type":"user","_id":"2","_version":3,"_shards":{"total":2,"successful":2,"failed":0}}[hadoop@master elasticsearch-2.4.0]$ 
[hadoop@master elasticsearch-2.4.0]$ 
[hadoop@master elasticsearch-2.4.0]$ curl -XPOST http://master:9200/zhouls/user/2/_update?version=1  -d  '{"doc" :{"age" : 30}}'
{"error":{"root_cause":[{"type":"version_conflict_engine_exception","reason":"[user][2]: version conflict, current [3], provided [1]","index":"zhouls","shard":"2"}],"type":"version_conflict_engine_exception","reason":"[user][2]: version conflict, current [3], provided [1]","index":"zhouls","shard":"2"},"status":409}[hadoop@master elasticsearch-2.4.0]$ 
[hadoop@master elasticsearch-2.4.0]$ 
[hadoop@master elasticsearch-2.4.0]$ curl -XPOST http://master:9200/zhouls/user/2/_update?version=4  -d  '{"doc" :{"age" : 30}}'
{"error":{"root_cause":[{"type":"version_conflict_engine_exception","reason":"[user][2]: version conflict, current [3], provided [4]","index":"zhouls","shard":"2"}],"type":"version_conflict_engine_exception","reason":"[user][2]: version conflict, current [3], provided [4]","index":"zhouls","shard":"2"},"status":409}[hadoop@master elasticsearch-2.4.0]$ 
[hadoop@master elasticsearch-2.4.0]$ 
[hadoop@master elasticsearch-2.4.0]$ 

 

 

 

 

 

　　更多，請見

Elasticsearch筆記三之版本控制和插件