Scan times steadily increasing

[Chris <cp...@embarqmail.com>]

SA 3.3.0, Mandriva 2010, not a mail server just a single user desktop.
As shown below the ham/spam scan times have been increasing steadily
since the 4th of April and I can't figure out why. I have named running
as a local caching name server
04/04/2010
Email:   23  Autolearn:     0  AvgScore: -29.78  AvgScanTime: 10.59 sec
Spam:     5  Autolearn:     0  AvgScore: 110.00  AvgScanTime:  8.02 sec
Ham:     18  Autolearn:     0  AvgScore: -68.61  AvgScanTime: 11.31 sec

04/16/2010
Email:  165  Autolearn:     0  AvgScore:   2.88  AvgScanTime: 33.22 sec
Spam:    44  Autolearn:     0  AvgScore:  72.43  AvgScanTime: 18.38 sec
Ham:    121  Autolearn:     0  AvgScore: -22.40  AvgScanTime: 38.62 sec

I took a typical ham message and ran it against 'spamassassin -D -t' and
got an almost 58 second scan time:

14.92user 0.51system 0:57.42elapsed 26%CPU

Looking at the DNSBL query times (min and max) it seems a bit excessive:

async: timing: 0.350 . A:ns.visi.com.
async: timing: 4.816 . DNSBL:zen.spamhaus.org.:3.1.101.149
async: timing: 4.832 . DNSBL:zen.spamhaus.org.:6.1.101.149
async: timing: 4.835 . DNSBL:zen.spamhaus.org.:138.98.254.66
async: timing: 4.837 . DNSBL:zen.spamhaus.org.:1.98.98.209

I ran a couple of typical spam through and got times like this (min and
max):

async: timing: 0.043 . NS:dnswl.org
async: timing: 1.364 . DNSBL:zen.spamhaus.org.:1.71.52.72

13.96user 0.33system 0:36.10elapsed 39%CPU

async: timing: 0.034 . NS:sorbs.net
async: timing: 0.619 . DNSBL:zen.spamhaus.org.:2.32.93.143

13.57user 0.34system 0:45.82elapsed 30%CPU

I do have short-circuit running and it works well when the clam plug-in
hits on a spam and when the ham rules I have are hit but the scan times
just seem to be constantly increasing. Anything I can do to troubleshoot
this further?

Chris

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