Suppose you have a very small polling interval, and a message system that does not preserve the order in which messages arrive. It may be common for out-of-sequence messages to arrive after two or three polls have been completed. In this example, it is recommended that you use the -rp option to increase the SQL Remote Message Agent (dbremote) patience so that a large number of unnecessary resend requests are not sent. The -rp option is often used in conjunction with the -rd option that sets the polling interval.

There are two remote users, named user1 and user2, both of which run the SQL Remote Message Agent (dbremote) with a polling interval of 30 seconds and a patience of 3 polls. For example, they use the following command to run their SQL Remote Message Agents (dbremote):

dbremote -c "DSN=SQL Anywhere 12 Demo"  -rd 30s -rp 3

In the following sequence of operations, messages are marked as userX.n where X is the user name and n is the message number. For example, user1.5 is the fifth message from user1. The SQL Remote Message Agent (dbremote) expects messages to start at number 1 for both users.

At time 0 seconds:

At time 30 seconds:

At time 60 seconds:

At time 90 seconds:

When a user receives a new message, it resets the SQL Remote Message Agent (dbremote) patience even if that message is not the one expected.

At time 120 seconds:

• Performance when receiving messages
• Polling interval adjustments to check for new messages
• Throughput adjustments by caching received messages
• Adjusting the number of worker threads
• Performance when sending messages