Yingjie Cao created FLINK-14872:
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             Summary: Potential deadlock for task reading from blocking 
ResultPartition.
                 Key: FLINK-14872
                 URL: https://issues.apache.org/jira/browse/FLINK-14872
             Project: Flink
          Issue Type: Bug
            Reporter: Yingjie Cao


Currently, the buffer pool size of InputGate reading from blocking 
ResultPartition is unbounded which have a potential of using too many buffers 
and may lead to ResultPartition of the same task can not acquire enough core 
buffers and finally lead to deadlock.

Considered the following case:

Core buffers are reserved for InputGate and ResultPartition -> InputGate 
consumes lots of Buffer (not including the buffer reserved for ResultPartition) 
-> Other tasks acquire exclusive buffer for InputGate and trigger redistribute 
of Buffers (Buffers taken by previous InputGate can not be released) -> The 
first task of which InputGate uses lots of buffers begin to emit records but 
can not acquire enough core Buffers (Some operators may not emit records out 
immediately or there is just nothing to emit) -> Deadlock.

 

I think we can fix this problem by limit the number of Buffers can be allocated 
by a InputGate which reads from blocking ResultPartition.



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