Problems with SpamAssassin 3.0.1 timing out

[Paul Welsh]

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Recently and perhaps since installing MailScanner 4.36.4, I've had problems
with SpamAssassin 3.0.1 timing out.  This is causing my whole server to slow
down and today got to ridiculous levels with spamassassin timing out and
being killed 832 times.

I am also getting this kind of thing:

rejecting connections on daemon MTA: load average: 12

If I run spamassassin -tD on a message I can see lots of these lines:

debug: plugin: Mail::SpamAssassin::Plugin::URIDNSBL=HASH(0x848e404)
inhibited further callbacks

though from googling I realise these may not be significant.

I then see loads of warnings like this:

debug: URIDNSBL: query for welshfamily.com took 9 seconds to look up
(multi.surbl.org.:welshfamily.com)
debug: URIDNSBL: query for welshfamily.com took 11 seconds to look up
(sbl.spamhaus.org.:1.50.245.194)

Clearly these URIDNSBL lookups are causing the problem.

I altered my local.cf file to exclude the URIDNSBL lookups.  I would have
liked to have left in the SBL check which I have found the most effective,
but it causes too many delays:

score URIBL_AB_SURBL 0
score URIBL_OB_SURBL 0
score URIBL_PH_SURBL 0
score URIBL_SBL 0
score URIBL_SC_SURBL 0
score URIBL_WS_SURBL 0

This has helped, but the performance problem remains.

I installed the latest Net::DNS (version 0.48) but it seems to have made no
difference.

spamassassin --lint doesn't indicate any rule problems.

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