MySQL Bugs: #120774: replication worker thread dealock

Bug #120774	replication worker thread dealock
Submitted:	25 Jun 12:16
Reporter:	Smith Tim	Email Updates:
Status:	Open	Impact on me:	None
Category:	MySQL Server: Replication	Severity:	S2 (Serious)
Version:	8.4.8	OS:	Linux
Assigned to:		CPU Architecture:	Any

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Description:
I encounter that replication worker threads get stuck frequently due to deadlock between worker threads. After analyzing the issue, I find someone has already written an article https://medium.com/@slow_tech/case-study-why-mysql-parallel-replication-can-be-slower-than... about the root cause.

How to repeat:
Please refer to the reproduce steps at the article https://medium.com/@slow_tech/case-study-why-mysql-parallel-replication-can-be-slower-than....

Suggested fix:
Given that users could not prevent deadlock between replication worker threads, MySQL should have a way to prevent it. Alternatively, at least break the deadlock immediately instead of waiting for the timeout passively.