[imp] Improving IMP message load times

[Michael M Slusarz]

Quoting Mat Cantin <mat at cantinbrothers.ca>:

> Greetings,
>
> I currently have Horde4 groupmail installed and operational on  
> Lighttpd with the Dovecot IMAP backend for email and authentication.  
> I've been working on trying to improve IMP's performance when  
> loading new messages that have not yet been viewed and cached. I've  
> been able to get it down to about 3 seconds, which I understand is  
> pretty typical because that's how long it takes to establish a new  
> IMAP session and download the message.

3 seconds?  According to Firebug, it took 453ms total to view your  
message, from the initial browser request to receiving the full  
response from the server (granted, my mail server is located about 25  
feet away in my basement, so network latency is essentially zero, but  
still...)

You are using the dynamic view right?  Traditional view will take much  
longer because it needs to rebuild the entire page on every view (and  
it is even worse if you have the sidebar open).  Dynamic view only  
needs to prepare the message view data when viewing a message.

> Although 3 seconds is good, when my users want to look through  
> several new messages quickly, it's really not that great, especially  
> when comparing the performance with Google Mail and Outlook Web  
> Access.

Have you tried the recommendations in imp/docs/PERFORMANCE?   
Specifically using imapproxy?

> Getting to the point, I've noticed that once a message has been  
> viewed and cached, going back to that message later is  
> instantaneous. Does anyone know if it's possible to configure IMP to  
> pre-cache all the messages in the current view? Ideally, it could  
> quickly load and show the user's message list and then proceed to  
> download the messages in the background. I realize that this will  
> obviously take more server resources, but that's a trade-off we can  
> make.

There should be no need to pre-cache.  500ms to view a message is more  
than fast enough.

michael

___________________________________
Michael Slusarz [slusarz at horde.org]