On 1.1.2010, at 20.19, Michael wrote:

I would a method for Dovecot to recalculate the quota usage and rewrite it to the quota DB (Called on demand by a non-Dovecot POP3 daemon)

I don't want the line deleted in the DB as this would only recalculate next time the Dovecot LDA or IMAP handles a message, and I want to keep the data availability contiguous.

The best you can do now is to delete the row, connect to IMAP as the user and issue GETQUOTAROOT INBOX command. In future I suppose there should be some doveadm command to do this.