[imp] IMP stays slow with utilizations

[Anil Madhavapeddy]

Quoting Lista IMP <imp@help4u.com.br>:

> i've noted that for new users, my imp is very good and fast, bat when the 
> size of the mailboxes of the users grow up, the program stays very slow to 
> deal with the e-mails.

This will happen as the mailbox size increases, as IMP has to retrieve
every single one of the headers and sort them when it opens a mailbox.

We have some plans to sort this out in the future, such as a caching
IMAP proxy, but I really haven't had the time to look at it recently

(I still have some C++ STL code lying around, but I'm going to rewrite
it in C using djblib when I get the time)

> is the size of the mailboxes the problem that slow down my connections?

Yes.  If you are using a maildir based server, then the size of the 
mailbox doesn't matter, just the number of messages.  This is the case
with Courier-IMAP and Cyrus (although it uses indexed maildirs).

If you are using UW-IMAP, then I suspect it'll slow down if you have
a few large messages, as it has to read the entire file in to process
it.

> if it is the reason, there is a way to me bypass this problem, maybe 
> changing imap by pop3??

Changing to POP3 certainly wouldn't help (probably make things a 
bit worse, especially with regards to attachment handling).

For the moment, cut down on mailbox size, or get a faster machine! :)

-- 
Anil Madhavapeddy, <anil@recoil.org>