Advanced Queuing - Oracle

Propagation Features
Java (JDBC): Example Code
No example is provided with this release.
Enhanced Propagation Scheduling Capabilities
Detailed information about the schedules can be obtained from the catalog views
defined for propagation. Information about active schedules—such as the name of
the background process handling that schedule, the SID (session, serial number) for
the session handling the propagation and the Oracle instance handling a schedule
(relevant if Real Application Clusters are being used)—can be obtained from the
catalog views. The same catalog views also provide information about the previous
successful execution of a schedule (last successful propagation of message) and the
next execution of the schedule.
For each schedule, detailed propagation statistics are maintained:
The total number of messages propagated in a schedule
Total number of bytes propagated in a schedule
Maximum number of messages propagated in a window
Maximum number of bytes propagated in a window
Average number of messages propagated in a window
Average size of propagated messages
Average time to propagated a message
This includes the total number of messages propagated in a schedule, total number
of bytes propagated in a schedule, maximum number of messages propagated in a
window, maximum number of bytes propagated in a window, average number of
messages propagated in a window, average size of propagated messages and the
average time to propagated a message. These statistics have been designed to
provide useful information to the queue administrators for tuning the schedules
such that maximum efficiency can be achieved.
Propagation has built-in support for handling failures and reporting errors. For
example, if the specified database link is invalid, the remote database is unavailable,
or if the remote queue is not enabled for enqueuing, then the appropriate error
message is reported. Propagation uses an exponential backoff scheme for retrying
propagation from a schedule that encountered a failure.
If a schedule continuously encounters failures, the first retry happens after 30
seconds, the second after 60 seconds, the third after 120 seconds and so forth. If the
8-114 Oracle9i Application Developer’s Guide - Advanced Queuing