On Wed, 2007-05-16 at 08:24 -0400, Bill Boebel wrote:

Looks like in Cyrus, sorting by Received date is faster than sorting by the Sent header date because of the way they use the index and cache files... http://www.emaildiscussions.com/showpost.php?p=419246

Is this the case in Dovecot as well?

In Dovecot v1.0 both of the dates are stored in dovecot.index.cache file, so they're just as fast (as long as they're both cached already, if neither is cached then getting the received date is faster because it requires a single stat() with maildir instead of parsing message headers).

In Dovecot v1.1 the sort information is stored in dovecot.index file, so again they're just as fast.

I'm not actually sure how great of an idea it was to put the sort information into dovecot.index files. Sure it makes SORT faster, but it increases dovecot.index's size which makes other operations slower. It might be faster overall, but it might be even better to have a separate sort file. Except that's how I originally thought about doing it, but then decided that wasn't good. Maybe some day I'll figure out the optimal solution. :)