Email Speed
My new timing code revealed that there was a problem with all of the pages on the website that generate email.
I investigated a bit more and it turns out that using the Python smtplib is many times slow than using popen2 to call the sendmail command directly.
It also means that my Apache processes aren’t tied up waiting for email to process. The downside is that I need to do a bit more checking on the validity of email addresses in my application instead of relying on the mail server.