On Thu, 2010-11-18 at 10:08 -0200, Alex Baule wrote:

How doveadm purge a email ?

By "purge" do you actually mean the "doveadm purge" command that works only for multi-dbox? Or I'm guessing more likely you mean "doveadm expunge"?

It's search using the index or scan every directory and open the email to match the search criteria ?

This doesn't have much to do with expunging, or even doveadm really. It's done the same way for all doveadm's mail commands (search, fetch, expunge, altmove, etc.) The actual search code is also the same as used by IMAP SEARCH.

So, yeah, it'll use indexes as best as it can, but if you try to search based on something that's not in index/cache file (like message body), it'll have to open the mails.

On Thu, 2010-11-18 at 16:21 -0200, Alex Baule wrote:

I will create a schedule to expurge older emails than a date, like 3, 6 months.

Yes, in that case the dates are looked up from dovecot.index.cache files.

Maybe i will create a application that makes a pipe to doveadm and call it to do the job.

BTW. It's possible to talk to doveadm server as well via unix/tcp sockets. By default there is $base_dir/doveadm-server unix socket.