I have the same performance problem!!
A mailbox with 1500 messages takes minutes (!) to load. I also get errors like this in the log: [09-Nov-2005 23:07:50] PHP Fatal error: Allowed memory size of 8388608 bytes exhausted (tried to allocate 1024 bytes) in /var/www/roundcube/program/lib/imap.inc on line 1412
I noticed that the identical imap core is used as Ilohamail. But when I'm using Ilohamail, I do not have the performance issues!! This made me wonder, because i want to use RoundCube...
When I look in the code, I found this line in function _list_headers (in file program/include/rcube_imap.inc): $a_header_index = iil_C_FetchHeaders($this->conn, $mailbox, "1:$max");
This means it will fetch the complete imap folder in memory! When I changed the line in: $start = $max - 40; $a_header_index = iil_C_FetchHeaders($this->conn, $mailbox, "$start:$max");
This wil only fetch the last 40 messages. Now, all the performance problems are solved! Just in a few seconds I can login, and open messages very quickly! But I guess this will break a lot of functionality, like sorting and pagination..? (I don't know the code that well...)
Could this somehow get implemented, so RoundCube works also great with larger mailboxes? (For the record: I'm using Courier-imap as well on the local machine, but I do have good performance with squirrelmail AND server-side sorting)
Pieter.