Details
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Bug
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Status: Open
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Major
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Resolution: Unresolved
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3.5.0, 4.0.0, 3.5.1
Description
Expired sessions are regularly checked and cleaned up by a maintenance thread. However, currently, this process is synchronous. Therefore, in rare cases, interrupting the execution thread of a query in a session can take hours, causing the entire maintenance process to stall, resulting in a large amount of memory not being cleared.
We address this by introducing asynchronous callbacks for execution cleanup, avoiding synchronous joins of execution threads, and preventing the maintenance thread from stalling in the above scenarios. To be more specific, instead of calling runner.join() in ExecutorHolder.close(), we set a post-cleanup function as the callback through runner.processOnCompletion, which will be called asynchronously once the execution runner is completed or interrupted. In this way, the maintenance thread won't get blocked on joining an execution thread.