User's Manual

In the following sequence of operations, messages are marked as

userX.n

that user1.5 is the sixth message from user1. The Message Agent expects

messages to start at number 1 for both users.

At time 0 seconds:

1. The Message Agent reads user1.1, user2.4

2. The Message Agent applies user1.1

3. The Message Agent patience is now user1: N/A, user2: 3, as an out of

sequence message has arrived from user 2.

At time 30 seconds:

1. The Message Agent reads: no new messages

2. The Message Agent applies: none

3. The Message Agent patience is now user1: N/A, user2: 2

At time 60 seconds:

1. The Message Agent reads: user1.3

2. The Message Agent applies: no new messages

3. The Message Agent patience: user1: 3, user2: 1

At time 90 seconds:

1. The Message Agent reads: user1.4

2. The Message Agent applies: none

3. The Message Agent patience user1: 3, user2: 0

4. The Message Agent issues resend to user2.

When a user receives a new message, it resets the Message Agent patience

even if that message is not the one expected.

Tuning the message sending process

The turnaround time for replication is governed by how often each sites

sends messages and how often each site polls for incoming messages. To

achieve a small time lag between data entry and data replication, you can set

a small value for the -sd Message Agent option, which controls the

frequency for polling to see if more data needs to be sent.

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