[Dovecot] Procmail and dovecot interactions

Hi,

I'm using procmail to deliver to Maildir directories:

DEFAULT=${HOME}/Maildir/

I notice dovecot keeps a 'dovecot-uidlist' plus cache and index files, in each maildir. How is it that dovecot keeps these up to date when the contents of cur/ keeps changing?

Is dovecot scanning cur/ every so often checking for changes? Isn't this slow for large folders (100k+)?

I note on the Dovecot LDA page[1], that it keeps the "Dovecot index base up to date". Does this mean Dovecot isn't expected to work properly with a delivery agent which doesn't know about its indexes?

Cheers, Jeff

[1] http://wiki.dovecot.org/LDA