Overriding dovecot.conf from Userdb Extras

Hi,

I thought I read that anything from dovecot.conf can be overridden in a userdb lookup. Or a passdb lookup with "userdb_" prefix.

But I tried for fun change log_path but it never worked. Is that because logging is special, already started logging before it comes to the passdb/userdb lookups? So are there some dovecot.conf settings that cannot be overridden?

Thanks!