Problem with mysql postfix backend with amavisd

[rsmits-l]

Hello,

We have an issue with our mailrelay system. Amavisd with spamassassin. 
Backend is Postfix with HASH db and mysql database. When the mail starts 
coming in, everything looks fine, but after a few minutes we see a lot 
of these errors.

----------------------------------
Main.cf :
Works fine :
virtual_alias_maps = hash:/home/postfix/namen

Errors :
virtual_alias_maps = hash:/home/postfix/namen, 
mysql:/home/postfix/forwardsqlconnect.cf
----------------------------------

Temporary lookup failure; from=<X.XXXXXXXX at tudelft.nl> 
to=<xxxxxxxx at gmail.com> proto=ESMTP helo=<localhost>

Jun 26 14:25:27 mx4 amavis[8448]: (08448-02) smtp resp to RCPT (pip) 
(<xxxxxxxx at gmail.com>): 451 4.3.0 <xxxxxxxx at gmail.com>: Temporary lookup 
failure

This happens only if the mysql backend is being used. If the mysql is 
being turned off in the config everything works as expected. Our setup 
is as followes :

--> 25 / Postfix / smtpd
--> 127.0.0.1:10026 / amavisd
After spamcheck
--> 127.0.0.1:10027 / Postfix smtpd
Delivers to final recipient.

We have noticed that recipient translations are being done twice. First 
before, and again after the spamcheck. We think the second translation 
is going wrong sometimes. Is there a way to disable recipeint check on 
second smtpd hop. (More of a question to postfix list)

Can anyone help with this error ? Mysql database performance issue is 
not the case. After extensive monitoring we found that max connections 
and memory is fine.

Greetings, Richard Smits.