qpsmtpd-forkserver seems awfully slow

[John L]

I have two SMTP servers on my mail host, one mostly for abuse.net, one for 
everything else.  At the moment the abuse.net one is running 
qpsmtpd-forkserver, typically with about 15 connections, the majority of 
the connections disposed of before DATA either by greylisting or some 
heuristics that identify invalid abuse.net addresses.  The other one is 
running a patched qmail-smtpd, typically under 10 connections, maybe half 
greylisted, most of the rest are on DNSBLs which rather than rejecting I 
accept and send into a spamtrap, with a 550 at the end of data for good 
measure.  The load average hovers around 1.

I turned off the qmail-smtpd and added its IP to qpsmtpd, and it went 
nuts, 90 processes, load averages upwards of 15.  I have some custom 
plugins, a couple that make very cheap UDP calls, to check greylisting and 
to check whether a rcpt address is valid, a couple that pass mail that 
survives the DNSBLs and heuristics to DCC and spamassassin, and one that 
logs all the messages in a MySQL database (not the message body, just 
envelope, IPs, and some flags.)

When I did a top command, it was all perl qpsmtpd processes running.  Any 
idea what the problem is?

I'm not averse to trying qmail-async, but it's not clear how I can make 
that work with the mysql library.

R's,
John