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https://issues.apache.org/jira/browse/CXF-7122?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15643233#comment-15643233
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Freeman Fang commented on CXF-7122:
-----------------------------------

Hi William,

FYI, with your original patch, with the AsyncHTTPConduitTest I appended, you 
can run into infinite loop also with 
AsyncHTTPConduitTest#testTimeout, so both the sync and async way has the 
infinite loop issue. If you will re-work a solution, please also consider this.

Btw, the SocketTimeoutException name may not be appropriate for all case, we 
can reconsider to use more accurate exception name like RecieveTimeoutException 
after the real issue get resolved.

And if you wanna more help from community to resolve the issue you ran into, a 
reproducer test case definitely would be more helpful.

Thanks 
Freeman

> Infinite loop due to AsyncHTTPConduit read timeout with exhausted connection 
> pool
> ---------------------------------------------------------------------------------
>
>                 Key: CXF-7122
>                 URL: https://issues.apache.org/jira/browse/CXF-7122
>             Project: CXF
>          Issue Type: Bug
>          Components: Transports
>            Reporter: William Montaz
>            Assignee: Freeman Fang
>            Priority: Critical
>             Fix For: 3.2.0, 3.1.9
>
>         Attachments: AsyncHTTPConduitTest.java
>
>
> Using AsyncHTTPConduit, when the underlying connection pool gets exhausted, 
> requests waiting for a connection will lead to an infinite loop if they reach 
> receive timeout.
> The problem occured on all versions of CXF above 3.0.5 (we did not tested 
> other ones). 
> Let's imagine a backend that's broken and leads to timeout for all requests.
> When handling requests, the cxf worker thread will eventually go in wait 
> state (AsyncHTTPConduit:618), with a timeout that matches the 
> HTTPClientPolicy.setReceiveTimeout() value, waiting for the NIO stack to 
> complete and call notifyAll via responseCallback (AsyncHTTPConduit:455). 
> The timeout on the wait is the big problem :
> With our broken backend, the connection pool is exhausted waiting for other 
> requests to timeout. When a new request is made by cxf against this backend, 
> after timeout time this will happen :
>  - on the one side the reactor threads will get a connection from the pool 
> and try to write to the output stream. Waiting in the pool is not considered 
> as receive timeout.
>  - on the other side the cxf worker thread will wake up (because of the 
> timedout wait), and shutdown SharedOutputBuffer and SharedInputBuffer 
> (AsyncHTTPClient:624)
>  - reactor threads will go to infinite loop because they will try to 
> produceContent from a shutdown buffer (SharedOutputBuffer:120)
>  
>  From there, application recovery is compromised.
>   
>  To fix that, timeout should be handled only via the client callback 
> (AsyncHTTPConduit:463).



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