MCP Efficiency?

Julian Field MailScanner at
Fri Aug 18 09:26:46 IST 2006

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David Jacobson wrote:
> Hi Guys / Julian,
> We've noticed some load problems using MCP.  We initially thought it had
> to do with the MCP spam.assassin.prefs using all the SA plugins...
> We enabled MCP on one domain on a server that's load average is 3 as we
> enable MCP the load jumps to 15.
Yes, the load cost is very high.
> I'm concerned how this can happen as it's just scanning 1 domain out of
> 100's that does very minimal mail on the server the ruleset is to use
> MCP for one domain.  
> Julian, do you perhaps know of any problems with this code in terms of
> speed?  As far as I'm concerned if it's enabled for one domain with
> minimal volume it should not immediately jump the load on the server to
> 15.  I did a watch on ps and noticed the MCP check only comes once every
> like 5-10 minutes for a few seconds.
Currently, I do the MCP checks on every batch unless there is an 
explicit MCP Checks = no in MailScanner.conf. If any domain uses it, 
then it is called for every batch of messages.

What I could do to improve the situation is check every message in the 
batch to see if that message produces a "yes" answer from a ruleset. If 
no messages produce a "yes" then don't call MCP.

That should relieve your problem nicely.

Prepared to test it for me if I post a patch?

> Thanks in advance.

- -- 
Julian Field
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