[jira] [Resolved] (CXF-7122) Infinite loop due to AsyncHTTPConduit read timeout with exhausted connection pool

["Freeman Fang (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/CXF-7122?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Freeman Fang resolved CXF-7122.
-------------------------------
       Resolution: Fixed
    Fix Version/s: 3.1.9
                   3.2.0

> 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
>
>
> 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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