[whishlist] new option for 'doveadm purge'

[Michael Grimm]

Hi,

I do store mail in mdbox format of 150m in size (dovecot 2.3.9). 

Once in a while I do experience mdbox files of smaller size, even after applying 'doveadm purge' and previous expunges by the users. like:

-rw-------  1 vmail  dovecot  104854595 Feb  9  2019 /var/mail/.maildirs/userX/storage/m.22
-rw-------  1 vmail  dovecot   29088478 Mar  8  2019 /var/mail/.maildirs/userX/storage/m.31
-rw-------  1 vmail  dovecot   98210890 Mar 20  2019 /var/mail/.maildirs/userX/storage/m.39

(Currently the counter is at file number 129.)

Well, I never experienced missing mail or alike, but these "holes" in filesize irritates me, and yes, it is more or less a cosmetic issue. 

Nevertheless, I do sometimes want to get rid of these "holes" by backing up all mail and re-injecting the backup into a vanilla account of that user. And I used this approach when I wanted to store all mail messages in larger mdbox files; again, rather a cosmetic issue.

BUT that takes a very, very long time contrary to the speed of 'doveadm purge'. Unfortunately, that command starts somewhere with more recent mdbox files and never from scratch (oldest mdbox file).

Whishlist: Would it be much of an effort to implement an option like:

	'doveadm purge -f' 
	and '-f' standing for 'force' or 'from scratch' or 'from the very first message found' or 'you name it'?

Thanks in advance and thanks for Dovecot and with kind regards,
Michael