[lug] postfix speed optimization

[Ben Luey]

> Are they either SASL authenticating, or in the "mynetworks"?  Because your
> recipient restrictions should short-circuit in those two cases and not fall
> through to the check_recpient_access rule, in:
>
>> smtpd_recipient_restrictions =
>>           permit_mynetworks
>>           permit_sasl_authenticated,
>>           reject_non_fqdn_recipient
>>           reject_unauth_destination,
>>           check_recipient_access hash:/etc/postfix/access,
Yes, I believe my users are bypassing the check_recipient_access because 
they are either local (line 1) or SASL authenticated (line 2). However, 
I believe the slow query is not the check_recipient_access but my 
(virtual) aliases file (which is a hash, ldap, and sql lookup). So even 
for local users, when I connect and say "I'm sending mail to local user 
john", postfix does a slow ldap and sql query to see if john is an 
alias, when that fails, it says 'oh John is a local user, we are good. 
Or if I send mail to john at gmail.com, postfix still does the slow alias 
lookup and when that fails, says 'sending to remote user, ok send me the 
email message'. I want to delay this query until after accepting the 
message -- or at least limit that slow query to run only if recipient is 
local and isn't found in an earlier lookup. Or maybe I need to find a 
better way to do a mailing list  -- currently I'm having postfix look up 
aliases against my mailing list db. But the query is slow and sadly 
running 99.5% on queries that produce no results as most emails aren't 
being sent to the mailing list.

Ben