On Wed, 24 Apr 2002, Ashley Yakeley wrote: > What is the best way for an IMAP client to detect recently arrived mail > in a hierarchy of around a thousand mailbox folders? Should it do a > SELECT on each one periodically? Or should it open up 1000 connections, > SELECT a folder and do IDLE on each one?
The latter method is the least burdensome for long-term probing of a thousand messages, since it operates on a principle of server "push" rather than polling with a client "pull". No properly-designed system should have a problem with that many sessions. However, there is a cost in authentication; and in some servers the cost of authentication is greater than polling via STATUS. The right solution is not to use IMAP for this at all, but rather a facility that is specifically designed for "push" announcements of updates to large numbers of mailboxes. There is currently not a widely-available facility which meets this criteria, but it's being worked on.
