[Dovecot] Speed up mail retrieval by keyword

Hi,

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?

Versions in use are Roundcube 0.9.0 and Dovecot 2.1.10 (Maildir).

Thanks

Manfred

Links:

[1] https://github.com/umount/message_label