Conference iosg::all-in-1_v30

1487.0. "MAIL SEND on distribution lists" by KERNEL::OTHENJ () Wed Sep 23 1992 10:31

Hello,

	ALL-IN-1 v2.4

	Can someone give me a better explanation on how the MAIL SEND 
function works on local addressees?

	Here is my understanding so far;

	When a mail message is sent to the same person on a mail message 
twice, they only receive one copy of the mail message.

	When a mail message is sent to two distribution lists, both 
containing the same user, only one copy of the mail message is received.

	From this, I assume that the mail send code, when expanding the 
distribution lists, check that it has not already sent to a (local) user, 
and will not send it again if this is the case.

	The problem that the customer has found (and I can reproduce) is in 
the following scenario.

Sender is sending to two distribution lists @test1 and @test2. Fred Bloggs 
is included on both distribution lists, and each distribution list only 
contains local usernames.

	When the sender sends the mail message, the cursor remains flashing 
on line 24 for a couple of minutes, as there are at least 800 addresses on 
the expanded mail message. If Fred Bloggs gets a broadcast to see he has 
received this mail and IMMEDIATELY reads it, if the second occurence of his 
username on the second distribution list has not been processed, he will 
receive another copy of the mail message a few seconds later.
	
	I have managed to reproduce this by having two distribution lists, 
both with approx 50 usernames, but the username that I will test out is the 
first entry of the first distribution list, and the last entry in the 
second. If I read the mail as soon as it is broadcast, I receive a second 
mail message, but if I wait until the entire distribution has been sent, I 
only receive one mail.

	By looking at the header of the two mail messages, they both look 
exactly the same.

	Can someone explain to me how this processing works, and why this 
is happening. Does it check in pending for MAIL 'USERNAME' to see if an 
entry for this mail already exists?

	Thanks for any help?
	

		Julie
    

Hi,

The way "duplicate addresses" works is as follows.

When the mail is sent, ALL-IN-1 creates a record for the message in the
recipient's PENDING.DAT record.  If the message contains the same user twice,
ALL-IN-1 doesn't check this, it just tries to create another PENDING.DAT record
for the recipient for the same mail message.  As there is already a pointer for
that message, nothing happens (specifically: ALL-IN-1 notices that the record
is already there, so just ignores the recipient).

So under normal circumstances, duplicated recipients only get one copy of the
message, without ALL-IN-1 needing to take any special action.

However, if the recipient reads the message immediately after the
PENDING.DAT record is first written, the PENDING.DAT record is removed, and
a file cabinet entry created for the user instead.  So when the recipient
appears later in the addressee list, the second write to PENDING.DAT succeeds,
and the user receives the message again.

There isn't really anything you can do about it, but I hope it's now clear why
it's happening.

Scott