Socket read delay question

Question

I'm having a delay problem only on Solaris 10 using the Tomcat connector from IIS to Solaris.
I've posted this issue on a couple of Java forums with no luck. Hopefully, this forum will have the correct audience.
I have:
- IIS 6, Windows 2003 Server on dual PIII with jk 1.2.15 installed and working.
- Solaris 10 on Sun E420R with Quad Processors with jBoss / Tomcat version 4.0.3SP1 installed and working.
There is a significant delay in page loading that occurs randomly (every 10-20 clicks) which lasts for 10-18 or so seconds.
I've traced it to a read() method in the ChannelSocket.java file on the AJP (i.e. Tomcat / Solaris 10) side.
The delay always occurs while the receive() method is reading the header portion of the message.
The length of the header that the read is trying to read is 4 bytes. The call to BufferedInputStream()
will block until it gets these 4 bytes of the header (10-18 seconds). I've modified the Java code
and put a call in to available() before and after the read. The before returns 0 and the after returns 1138 or so.
I've tried every imaginable combination of configs on the IIS side to get around the problem ... and then
some kernel TCP/IP configs on the Solaris side ... too many to list here.
The problem seems to be isolated to Solaris ... because Linux, XP, Windows 2003 server all work without this problem.
My question is this ... is there any thing that I can configure to have this read return faster?
Changes to the Solaris kernel ... some config parameter ... ?? Anyone experience this before?
I'll gladly list the things I've tried to get some idea of how to solve this.
I think ultimately this is my problem: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4479751
Thanks in advance!

Answer 1

Hi!
Try this...
Socket connection = new Socket(server,port);
// use a Buffered*Stream as often as possible, because
// of the IP Packet Lengths...It Increases the
// network performance (but you DON'T need it)
// you'll send bytes or messages to the server in
// the OutputStream and receive answers from the
// server in the InputStream
int packetOutputBufferSize = connection.getSendBufferSize();
int packetInputBufferSize = connection.getReceiveBufferSize();
BufferedOutputStream bos = new BufferedOutputStream(connection.getOutputStream(),packetOutputBufferSize);
BufferedInputStream bis = new BufferedInputStream(connection.getInputStream(),packetInputBufferSize);
// sending data through the socket
// create your packet in a byte array
byte[] output = new byte[<packet-lenght>];
output[0]=<packet ID>
output[1]=....
bos.write(output,0,output.length);
// receiving data from the socket
byte[] input = new byte[<max-packet-length>];
int read=0;
int length=0;
while ((read=bis.read(input,length,(input.length-length)) > 0) {
length+=read;
if (length>=input.length) break;
// now your server output is in the bytearray 'input'
If it isn't possible to set a max packet size, use a bytearray as buffer and write it content into a ByteArrayOutputStream, thats something like a resizable write-only byte array. (you'll get the full content of it by calling the method ByteArrayOutputStream.toByteArray())
Maybe you want to check the packet content during receiving the bytes from the socket: Then you should use some read() method from the InputStream, but thats not very powerful.