New MS install is slow to an extreme

[DAve]

After much plugging away, double checking, triple checking and herding 
of cats I *think* we may out of the woods. I won't know until tomorrow 
AM when traffic picks up again. Here are my findings so far.

MailScanner 4.67.6
ClamAV 0.92.1
SpamAssassin 3.2.4

Virus Scanners = [clamav | clamavmodule] - There appears to be no real 
gain in running clamavmodule, some speed increase but not enough to be 
noticed. I have clamavmodule configured just to save some memory.

ClamAV Full Message Scan = yes - That is a killer, it seems to really 
increase processing time. I have it now set to no, and I have removed my 
MSRBL sigs.

Incoming Work Dir = tmpfs (mdmfs in FreeBSD) - Surprisingly little 
difference. I left it on a memory file system for now.

mailscanner.cf -> skip_rbl_checks 1 - Oddly does not do what it claims. 
SA is still doing rbl checks. I commented out the DNSEval plugin in 
v320.pre file and was rewarded with errors for my effort. Not certain 
what the correct method of disabling rbl checks in SA is now. Peter 
Farrow found a message where this has been seen already. 
http://markmail.org/message/xzqi5fmrbj3tfgg2

MailScanner batch size - With version 4.54.6 MS processed 10 messages 
per batch and kept up just fine. With version 4.67.6 it will grab 30+ 
messages which takes longer to process. Increasing MS children has no 
effect. More children working slower doesn't process more mail for me. I 
don't see where I can configure this.

I am currently seeing processing times of .8 to 20 seconds per message, 
generally around the 2 to 4 seconds mark. This is for batches of 1 to 10 
messages. I was seeing as much as 800 seconds for a batch size of 30 
messages this morning. So there has been improvement.

I am compiling my SA rules and I run my RBLs in the MTA (hence why I do 
not want rbl checking in SA).

Overall, my previous install of MS 4.54.6, Clam .92, and SA 3.1.9 would 
run rings around this install. I am seriously contemplating rolling back 
but I am uncertain if I have the original tarball for Julian's Clam+SA 
package.

I believe my issue is configuration of MS or SA at this point. I am open 
to suggestions.

Thanks for the help.

DAve

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