[Dovecot] index file vs. memory

[Marten Lehmann]

Hello,

we have a large base of mailbox users and while pop3-connections are 
usually closed after the download of all mails, I noticed hundrets of 
imap-connections kept idle by the users. This is surely according to the 
idea behind imap, but I'm a bit afraid of overwhelming memory 
consumption if there are too many imap-connections opened at the same 
time. Is the index file kept in memory as long as an imap-connection 
exists, or is it closed as soon as a certain read or write command has 
finished?

Regards
Marten