[Done][DUBBO] dubbo Thread pool is EXHAUSTED!

异常信息：

com.alibaba.dubbo.remoting.ExecutionException: class com.alibaba.dubbo.remoting.transport.dispatcher.all.AllChannelHandler error when process caught event .
        at com.alibaba.dubbo.remoting.transport.dispatcher.all.AllChannelHandler.caught(AllChannelHandler.java:67)
        at com.alibaba.dubbo.remoting.transport.AbstractChannelHandlerDelegate.caught(AbstractChannelHandlerDelegate.java:44)
        at com.alibaba.dubbo.remoting.transport.AbstractChannelHandlerDelegate.caught(AbstractChannelHandlerDelegate.java:44)
        at com.alibaba.dubbo.remoting.transport.AbstractPeer.caught(AbstractPeer.java:127)
        at com.alibaba.dubbo.remoting.transport.netty.NettyHandler.exceptionCaught(NettyHandler.java:112)
        at com.alibaba.dubbo.remoting.transport.netty.NettyCodecAdapter$InternalDecoder.exceptionCaught(NettyCodecAdapter.java:165)
        at org.jboss.netty.channel.Channels.fireExceptionCaught(Channels.java:525)
        at org.jboss.netty.channel.AbstractChannelSink.exceptionCaught(AbstractChannelSink.java:48)
        at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:296)
        at com.alibaba.dubbo.remoting.transport.netty.NettyCodecAdapter$InternalDecoder.messageReceived(NettyCodecAdapter.java:148)
        at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:268)
        at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:255)
        at org.jboss.netty.channel.socket.nio.NioWorker.read(NioWorker.java:88)
        at org.jboss.netty.channel.socket.nio.AbstractNioWorker.process(AbstractNioWorker.java:109)
        at org.jboss.netty.channel.socket.nio.AbstractNioSelector.run(AbstractNioSelector.java:312)
        at org.jboss.netty.channel.socket.nio.AbstractNioWorker.run(AbstractNioWorker.java:90)
        at org.jboss.netty.channel.socket.nio.NioWorker.run(NioWorker.java:178)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at java.lang.Thread.run(Thread.java:745)
Caused by: java.util.concurrent.RejectedExecutionException: Thread pool is EXHAUSTED! Thread Name: DubboServerHandler-192.168.120.213:20880, 
Pool Size: 200 (active: 200, core: 200, max: 200, largest: 200), Task: 3839523 (completed: 3839323), 
Executor status:(isShutdown:false, isTerminated:false, isTerminating:false), in dubbo://192.168.120.213:20880!
        at com.alibaba.dubbo.common.threadpool.support.AbortPolicyWithReport.rejectedExecution(AbortPolicyWithReport.java:53)
        at java.util.concurrent.ThreadPoolExecutor.reject(ThreadPoolExecutor.java:823)
        at java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:1369)
        at com.alibaba.dubbo.remoting.transport.dispatcher.all.AllChannelHandler.caught(AllChannelHandler.java:65)
        ... 19 common frames omitted

提示线程池满了，若有新请求进入的时候，会拒绝执行。

来一张官方的图：

上图Dispatcher后面跟着的ThreadPool就是我们所说的业务线程池。Dispatcher分为5类，默认是all，解释也直接参考官方截图：

而dubbo默认为all模式，查看源码（可见all模式下相关事件都使用了业务线程池）：

all模式下线程池：

修改dubbo配置文件：

    <dubbo:protocol name="dubbo" port="${dubbo.port}" accesslog="false" threads="500" dispatcher="message"/>

修改后，启用MessageOnlyChannelHandler，源码如下（此时只有receive业务方法独享线程池）：

参考： http://manzhizhen.iteye.com/blog/2391177

以上。