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Posted to reviews@iotdb.apache.org by GitBox <gi...@apache.org> on 2020/06/25 04:57:18 UTC

[GitHub] [incubator-iotdb] LebronAl opened a new pull request #1422: [Distributed]remove unnecessary persistence

LebronAl opened a new pull request #1422:
URL: https://github.com/apache/incubator-iotdb/pull/1422


   I found that it's unnecessary to persist meta after log's persistence in `SyncLogDequeSerializer`. Persisting meta is for security purposes.However, it is expensive to trigger the persistence meta every time a log is persisted, as this function only affects lastLogIndex, lastLogTerm, commitLogIndex and commitLogTerm, which can be inferred from the logs on disk under the current persistence policy. 
   
   I tested this change with iotdb-benchmark, you can see a 20 to 46 percent performance improvement.Since the disk on my test machine was SSD, the impact of random writes was not so great. If it was HDDS, the performance improvement would be more significant.
   
   ## benchmark config:
   ---------------------
   CLIENT_NUMBER=10
   GROUP_NUMBER=20
   DEVICE_NUMBER=20
   SENSOR_NUMBER=20
   BATCH_SIZE=50
   LOOP=10
   ---------------------
   ## session performance
   ### new version
   ![image](https://user-images.githubusercontent.com/32640567/85655877-aed0b900-b6e2-11ea-8245-7d135d15be02.png)
   ### old version
   ![image](https://user-images.githubusercontent.com/32640567/85656027-db84d080-b6e2-11ea-9f21-00c87821b0a5.png)
   
   ## jdbc performance
   ### new version
   ![image](https://user-images.githubusercontent.com/32640567/85655919-bb551180-b6e2-11ea-8c3d-50f4f5d4b868.png)
   ### old version
   ![image](https://user-images.githubusercontent.com/32640567/85656045-e17ab180-b6e2-11ea-9a95-0bac14d26a37.png)
   
   
   


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[GitHub] [incubator-iotdb] jt2594838 merged pull request #1422: [Distributed] Remove unnecessary persistence

Posted by GitBox <gi...@apache.org>.
jt2594838 merged pull request #1422:
URL: https://github.com/apache/incubator-iotdb/pull/1422


   


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