On 22.5.2013, at 22.31, Manfred Usselmann usselmann.m@icg-online.de wrote:

I' m using a roundcube plugin for adding attributes to mails, which are stored as IMAP keywords (https://github.com/umount/message_label [1]).

This plugin allows me to retrieve mails with a certain attribute across all my mail folders.

Selecting mails this way is very convenient, but also very slow, probably because I've got a lot of mails and folders.

Is there a way to speed this up somehow by changing any configuration options?

Instead of the Roundcube plugin you could use Dovecot's virtual plugin to create a virtual mailbox that contains all the mails with the keyword: http://wiki2.dovecot.org/Plugins/Virtual