I haven't been able to figure out what the reason is. It seems to have improved slightly to about 3/s but it still had 20 seconds delays occasionally for no apparent reason. I've since moved mail sending to a named version (rather than backend), and it works great. It can easily send 6/s, with one instance.
-- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appengine@googlegroups.com. To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
