Hello,
What is fetched depends upon the client software and what it asks for.
yes, but that may very extremely. If Cyrus only caches lets say "X-Spam" and there is no such header in the email and thus not in the cache, will Cyrus look into the file then? Or will the cache contain an empty header?
Some software asks for rather more, so you need to modify the server to cache more. Some software just asks for _all_ headers, eg MS Outlook. For those, you have problems but I believe there are patches around to cache all headers.
I think it would be a really great performance boost if cyrus would cache all headers (I think that is what dovecot does and is very fast with it) so it doesn't have to touch the files. Where have you seen such patches?
Regards Marten ---- Cyrus Home Page: http://cyrusimap.web.cmu.edu/ Cyrus Wiki/FAQ: http://cyrusimap.web.cmu.edu/twiki List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html