[jira] [Created] (IOTDB-5835) Fix wal accumulation caused by datanode restart

["Xinyu Tan (Jira)" <ji...@apache.org>]

Xinyu Tan created IOTDB-5835:
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             Summary: Fix wal accumulation caused by datanode restart
                 Key: IOTDB-5835
                 URL: https://issues.apache.org/jira/browse/IOTDB-5835
             Project: Apache IoTDB
          Issue Type: Improvement
            Reporter: Xinyu Tan
            Assignee: Xinyu Tan
         Attachments: image-2023-04-28-11-08-43-542.png, image-2023-04-28-11-08-51-622.png, image-2023-04-28-11-08-57-549.png, image-2023-04-28-11-09-03-902.png

When cluster is running properly, if replica A of a consensus group becomes the Leader, it continuously sends logs to other followers and updates wal's safelyDeletedSearchIndex after sending logs. wal files is deleted asynchronously. Therefore, if a restart occurs, some logs that have been synchronized to other nodes may not be deleted. After the restart, perhaps another replica B becomes the Leader and the current replica A becomes a Follower receiving logs.
Because the current IoTConsensus does not use its recovered syncIndex to set the safelyDeletedSearchIndex of the underlying walnode at startup, replica A cannot delete wal files at this time, which results in the accumulation of WAL files. Write requests of all regions on the node are affected.
 !image-2023-04-28-11-08-43-542.png|thumbnail! 
 !image-2023-04-28-11-08-51-622.png|thumbnail! 
 !image-2023-04-28-11-08-57-549.png|thumbnail!  !image-2023-04-28-11-09-03-902.png|thumbnail! 
The solution to this problem is to update the safelyDeletedSearchIndex of reader at startup



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