User's Manual

messages are flushed in a least-recently-used fashion.
This option is provided primarily for customers considering a single
consolidated database for thousands of remote databases.
Tuning incoming message polling
When running a Message Agent in continuous mode, typically at a
consolidated database site, you can control how often it polls for incoming
messages, and how “patient” it is in waiting for messages that arrive out of
order before requesting that the message be resent. Tuning these aspects of
the behavior can have a significant effect on performance in some
circumstances.
Issues to consider The issues to consider when tuning the message-receiving process are
similar to those when tuning the message-sending process.
♦ Regular messages Your choices dictate how often the Message Agent
polls for incoming messages from remote databases.
♦ Resend requests You can control how many polls to wait until an
out-of-order message arrives, before requesting that it be resent.
♦ Processing incoming messages If your polling period for incoming
messages is too long, compared to the frequency with which messages
are arriving, you could end up with messages sitting in the queue, waiting
to be processed. If your polling period is too short, you will waste
resources polling when no messages are in the queue.
☞ For more information on the message sending process, see “Tuning the
message sending process” on page 232.
Polling interval
By default, a Message Agent running in continuous mode polls one minute
after finishing the previous poll, to see whether new messages have arrived.
You can configure the polling interval using the -rd option.
The default polling interval from the end of one poll to the start of another is
one minute. You can poll more frequently using a value in seconds, as in the
following command line:
dbremote -rd 30s
Alternatively, you can poll less frequently, as in the following command line,
which polls every five minutes:
dbremote -rd 5
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