Does Flink operators synchronize states?

[Yuta Morisawa]

Hello,

I am wondering whether Flink operators synchronize their execution 
states like Apache Spark. In Apache Spark, the master decides 
everything, for example, it schedules jobs and assigns tasks to 
Executors so that each job is executed in a synchronized way. But Flink 
looks different. It appears that each TaskManagers are dedicated to 
specific operators and they asynchronously execute tasks. Is this 
understanding correct?

In short, I want to know how Flink assigns tasks to TaskManagers and how 
manage them because I think it is important for performance tuning. 
Could you tell me If you have any detail documentation?

Regards,
Yuta
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