On Sun, 28 Apr 2002, Jeremy Howard wrote: > Bob Finch wrote: > > >>>>>>"Jeremy" == Jeremy Howard <[EMAIL PROTECTED]> writes: > >>>>>> > >>>>>> > > > > Jeremy> Doing it in a content_filter lets you add headers that you > > Jeremy> can then handle in Sieve scripts on a per-user basis, > > Jeremy> which is faster and cleaner. > > > >Would it really be faster? > > > >I haven't played with Postfix content_filters much yet, but > >FILTER_README says "You can expect to lose about a factor of two in > >Postfix performance for transit mail that arrives and leaves via SMTP, > >provided that you create no temporary files". From the diagram, it > >appears that mail passes through Postfix twice, so it looks like the > >message will be written into the Postfix queue twice as well. > > > > > The time it takes Postfix to write out a queue file is nominal, compared > to the time it takes SpamAssassin to analyze an email. So the key to > speeding up the process is to call SpamAssassin as few times as > possible. In our content_filter we check if any of the recipients has > spam protection turned on, and if so we add the spam headers. If there > are multiple recipients with spam protection turned on, SpamAssassin > still only has to run once for the message, rather than once per recipient.
The other thing to point out is that the spam extension will work with any MTA ... content_filters are a postfix-ism ... and, my experiences with sendmail's milter is why I moved to postfix ...
