Question about batch sizes

[S Joyce]

Hello.  I am new to MailScanner, but it has been working very well since I
installed it last week.  Thanks to some help from folks on the list, I was
also able to fix a problem with my ClamAV configuration.

Now, I have a performance question.  My understanding is that each
MailScanner process grabs a "batch" of incoming mail from the queue
directory to process.  I see the 4 apparent options in MailScanner.conf
that control that processing:

>Max Unscanned Bytes Per Scan = 100000000
>Max Unsafe Bytes Per Scan = 50000000
>Max Unscanned Messages Per Scan = 30
>Max Unsafe Messages Per Scan = 30

Now, if I understand that correctly, MailScanner will look for viruses/spam
in a batch of messages that is at most 50,000,000 bytes or that consists of
at most 30 messages.  (I don't think I have a configuration that would keep
any message from being scanned--I believe they all are).

When I pull out a section of the logs, I see numbers like this:

>Mar 16 15:14:37 nike MailScanner[4125]: Virus and Content Scanning: Starting
>Mar 16 15:14:37 nike MailScanner[5637]: New Batch: Found 8 messages waiting
>Mar 16 15:14:37 nike MailScanner[5637]: New Batch: Scanning 2 messages,
>27107 bytes
>Mar 16 15:14:38 nike MailScanner[4485]: New Batch: Found 9 messages waiting
>Mar 16 15:14:38 nike MailScanner[4485]: New Batch: Scanning 1 messages,
>6594 bytes
>Mar 16 15:14:38 nike MailScanner[6718]: Virus and Content Scanning: Starting
>Mar 16 15:14:39 nike MailScanner[4125]: Uninfected: Delivered 1 messages
>Mar 16 15:14:39 nike MailScanner[4125]: New Batch: Found 9 messages waiting
>Mar 16 15:14:39 nike MailScanner[4125]: New Batch: Scanning 1 messages,
>10326 bytes
>Mar 16 15:14:40 nike MailScanner[6718]: Uninfected: Delivered 1 messages
>Mar 16 15:14:45 nike MailScanner[6718]: New Batch: Found 10 messages waiting
>Mar 16 15:14:45 nike MailScanner[6718]: New Batch: Scanning 1 messages,
>3233 bytes

My question is this--if a process, like 6718 above, finds 10 messages, is
it right that it only scan 1 from that batch?  I'm just wondering about
efficiency.  I am _not_ complaining about efficiency at all; rather, I'm
just trying to get a handle in my mind of how many messages each process
will grab in a batch.  (As a rule, very few messages in the queue appear to
be large.)

TIA for any response.
SJ List
sjlist at heidelberg.edu