I am writing a service using TomCat and am trying to understand the pipelining feature of HTTP1.1 and its implementation in Tomcat.
Here are my questions:
1] Is pipelining in TomCat parallel. i.e => After it gets a pipelined request, does it break it down into individual request and invoke all that in parallel? Here is a small test I did: From my tests it looks like, but I am trying to find an authorative document etc?
public static void main(String[] args) throws IOException, InterruptedException
{
Socket socket = new Socket();
socket.connect(new InetSocketAddress("ServerHost", 2080));
int bufferSize = 166;
byte[] reply = new byte[bufferSize];
DataInputStream dis = null;
//first without pipeline - TEST1
// socket.getOutputStream().write(
// ("GET URI HTTP/1.1\r\n" +
// "Host: ServerHost:2080\r\n" +
// "\r\n").getBytes());
//
// final long before = System.currentTimeMillis();
// dis = new DataInputStream(socket.getInputStream());
// Thread.currentThread().sleep(20);
// final long after = System.currentTimeMillis();
//
// dis.readFully(reply);
// System.out.println(new String(reply));
//now pipeline 3 Requests - TEST2
byte[] request = ("GET URI HTTP/1.1\r\n" +
"Host:ServerHost:2080\r\n" +
"\r\n"+
"GET URI HTTP/1.1\r\n" +
"Host: ServerHost:2080\r\n" +
"\r\n"+
"GET URI HTTP/1.1\r\n" +
"Host: ServerHost:2080\r\n" +
"\r\n").getBytes();
socket.getOutputStream().write(request);
bufferSize = 1000*1;
reply = new byte[bufferSize];
final long before = System.currentTimeMillis();
dis = new DataInputStream(socket.getInputStream());
Thread.currentThread().sleep(20);
final long after = System.currentTimeMillis();
dis.readFully(reply);
System.out.println(new String(reply));
long time = after-before;
System.out.println("Request took :"+ time +"milli secs");
}
In the above test, in test2 the response time is not [20*3 = 60+ ms]. The actual GET request are very fast. This hints that these are getting parallelized, unless I am missing something ?
2] What is the default pipeline depth in Tomcat? How can I control it ?
3] When allowing pipelining on server side for my service, do I need to consider anything else assuming that the client follows the http://www.w3.org/Protocols/rfc2616/rfc2616-sec8.html#sec8.1.4 spec while handling pipelining? Any experiences are welcome.
