[CAMEL-10179] Frequent BlockingOperationExceptions under load in NettyProducer.openChannel()

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.17.2
• Fix Version/s: 2.17.4, 2.18.0
• Component/s: camel-netty4
• Estimated Complexity: Unknown
• Assignee: Claus Ibsen
• Reporter: Michael Frankfurter
• Created: 25/Jul/16 10:02
• Updated: 20/Aug/16 13:40
• Resolved: 20/Aug/16 13:40

Description

I have a class that uses a netty4 producer. While doing some load testing, I started seeing a lot of stack traces like the following:

io.netty.util.concurrent.BlockingOperationException: DefaultChannelPromise@3ee2397e(incomplete)
        at io.netty.util.concurrent.DefaultPromise.checkDeadLock(DefaultPromise.java:391) ~[netty-all-4.0.34.Final.jar:4.0.34.Final]
        at io.netty.channel.DefaultChannelPromise.checkDeadLock(DefaultChannelPromise.java:157) ~[netty-all-4.0.34.Final.jar:4.0.34.Final]
        at io.netty.util.concurrent.DefaultPromise.awaitUninterruptibly(DefaultPromise.java:284) ~[netty-all-4.0.34.Final.jar:4.0.34.Final]
        at io.netty.channel.DefaultChannelPromise.awaitUninterruptibly(DefaultChannelPromise.java:135) ~[netty-all-4.0.34.Final.jar:4.0.34.Final]
        at io.netty.channel.DefaultChannelPromise.awaitUninterruptibly(DefaultChannelPromise.java:28) ~[netty-all-4.0.34.Final.jar:4.0.34.Final]
        at org.apache.camel.component.netty4.NettyProducer.openChannel(NettyProducer.java:468) ~[camel-netty4-2.17.1.jar:2.17.1]
...

It seems to be the same like in CAMEL-8193 but during the opening phase, not the closing phase.

I had a look at org.apache.camel.component.netty4.NettyProducer.openChannel(), line 468 and maybe using channelFuture..addListener(...) instead of channelFuture.awaitUninterruptibly(); at that point may fix this issue.

Would be great if somebody could take a look.