在并发测试下Java NIO的管道错误

Question

I am now building an event-driven server, using Java NIO

When I did ab -n 100 -c 100 localhost:8080/ , everything is fine. But when I did ab -n 10000 -c 1000 localhost:8080/ , error occurred!!

The part of the code:

resHeader.append("Host: MyServer" + CRLF);
resHeader.append("Connection: close" + CRLF + CRLF);
ByteBuffer temp = ByteBuffer.wrap(resHeader.toString().getBytes());--(ClientHandler.java:372)
while(temp.hasRemaining()) {
    client.write(temp);
}

The definition of client: client = (SocketChannel) key.channel();

java.io.IOException: Broken pipe
    at sun.nio.ch.FileDispatcher.write0(Native Method)
    at sun.nio.ch.SocketDispatcher.write(SocketDispatcher.java:29)
    at sun.nio.ch.IOUtil.writeFromNativeBuffer(IOUtil.java:69)
    at sun.nio.ch.IOUtil.write(IOUtil.java:40)
    at sun.nio.ch.SocketChannelImpl.write(SocketChannelImpl.java:336)
    at ClientHandler.sendResponse(ClientHandler.java:372)
    at ClientHandler.parseRequest(ClientHandler.java:218)
    at ClientHandler.writeKey(ClientHandler.java:136)
    at ClientHandler.execute(ClientHandler.java:51)
    at TcpServer.main(TcpServer.java:33)

After the error, I add this to the code:

ByteBuffer temp = null;
try {
    temp = ByteBuffer.wrap(resHeader.toString().getBytes());
    while(temp.hasRemaining()) {
        client.write(temp);
    }
} catch (IOException e) {
    System.err.println("TEST: " + temp.hasRemaining());
    System.out.println("connect:" + client.isConnected()
    // TODO Auto-generated catch block
    e.printStackTrace();
}

And when the errors pop up again, it prints "TEST: true" and "connect:true" which means that it does not finish writing. Why this happened?

Also, I used ab -c 1000 -n 10000 -r http://localhost:8080/

-r : Don't exit on socket receive errors.

    Concurrency Level:      1000
    Time taken for tests:   18.700 seconds
    Complete requests:      10000
    Failed requests:        1878

   (Connect: 0, Receive: 626, Length: 626, Exceptions: 626)

(PS: Using this -r I did not get the errors: java.io.IOException: Broken pipe )

Does this provide some useful information?

Answer 1

'Broken pipe' means that the peer closed the connection prematurely. It could do that under load for any number of reasons, none of which have anything to do with your code.