Experience Question

Question

Hello,
i implemented a simple mailer with javamail and all works fine. now the project is for a community with a lot of members and i tested the send performance with following code:
MTAtransport = MTAsession.getTransport("smtp");
MTAtransport.connect(SMTP_HOST, SMTP_USER, SMTP_PWD);
while (0 till 1000) {
  msg todos...
   MTAtransport.sendMessage( msg, msg.getAllRecipients() );
}Now my mail-server is Qmail on another host and the test runs 3min 30 on "small" 2GHz debian system.
How can i tune up the performance?
If they are some possibilities to make email packages with more then one email and transfer this to the mail server?
Thanks for your suggestions!

Answer 1

I think you'll find that the slowness is due to your mail server. Some mail servers will even purposely
slow you down to prevent you sending large amounts of spam.
A simple test to see how fast the client runs without the server is to replace the sendMessage
call with the following:
msg.writeTo(new BufferedOutputStream(new FileOutputStream("msg.txt")));
If that runs slowly, we need to look into how you're constructing your messages.
If that runs quickly, the problem is almost certainly your mail server.
You might try using multiple threads, each with their own connection, to see if sending
messages in parallel is faster.
You might also want to watch the JavaMail debug output to see if there's a large delay
before the connect, or after a certain number of messages are sent, or when sending
the list of recipients.