[clamav-users] clamscan suddenly taking 25 minutes for a single mail

[Eddie]

A POP3 proxy program I have running on a Debian 10.8 system, uses 
clamscan to check incoming e-mails.  At some point in the very early 
morning (US West Coast time) it suddenly started taking a very long time 
to scan each mail,  So much that the controlling process would time out 
before clamscan finished.  Up to this point it was running fine.

Running a test from the command line, on a very simple 1-line mail took 
around 25 minutes:

root at CleanMail:~# date ; clamscan test.msg -v  --no-summary ; date
Mon 05 Apr 2021 11:59:10 AM PDT
Scanning /root/test.msg
/root/test.msg: OK
Mon 05 Apr 2021 12:24:06 PM PDT
root at CleanMail:~#

Looking through the logs, I can't see anything happening in the period 
between the last good scan and the sloooooow ones.

Where should I be going next to track this down.

Cheers.