[jira] [Created] (IOTDB-6256) Deadlock when calling FLUSH

["Tian Jiang (Jira)" <ji...@apache.org>]

Tian Jiang created IOTDB-6256:
---------------------------------

             Summary: Deadlock when calling FLUSH
                 Key: IOTDB-6256
                 URL: https://issues.apache.org/jira/browse/IOTDB-6256
             Project: Apache IoTDB
          Issue Type: Bug
          Components: Core/Engine
            Reporter: Tian Jiang
            Assignee: Tian Jiang
             Fix For: master branch
         Attachments: image-2023-11-23-19-30-31-905.png, image-2023-11-23-19-36-00-222.png, image-2023-11-23-19-36-36-198.png, image-2023-11-23-19-39-32-027.png

There is a deadlock issue which can be triggered by the FLUSH command in the following condition:

1. The main thread constructs sub-threads of closing tsfiles.

!image-2023-11-23-19-30-31-905.png!

2. The last sub-thread is near its end and removes itself from ''closingSequenceTsFileProcessors''. Then the main thread breaks the while loop, holds ''closeStroageGroupCondition'', and uses ''future.get'' to wait for the sub-thread.

!image-2023-11-23-19-36-00-222.png!

!image-2023-11-23-19-36-36-198.png!

3. Unfortunately, since the main thread holds the condition, the sub-thread cannot hold it and gets stuck. The main thread is also blocked by the sub-thread through "future.get", so there is a deadlock.

!image-2023-11-23-19-39-32-027.png!

 

The solution is simple: there is no need for the main thread to wait for the sub-threads while holding the condition, and the waiting can be done outside of the synchronization block.



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