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SQL Anywhere 11.0.0 » SQL Remote » SQL Remote Administration » SQL Remote administration


The message tracking system

SQL Remote has a message tracking system to ensure that all replicated operations are applied in the correct order, no operations are missed, and no operation is applied twice.

Message system failures may lead to replication messages not reaching their destination, or reaching it in a corrupt state. Also, messages may arrive at their destination in a different order from that in which they were sent. This section describes the SQL Remote system for detecting and correcting message system errors, and for ensuring correct application of messages.

If you are using an email message system, you should confirm that email is working properly between the two machines if SQL Remote messages are not being sent and received properly.

The SQL Remote message tracking system is based on status information maintained in the remoteuser SQL Remote system table. The table is maintained by the Message Agent. The Message Agent at a subscriber database sends confirmation to the publisher database to ensure that remoteuser is maintained properly at each end of the subscription.

The remoteuser table is the sys.sysremoteuser system view.

Status information in the remoteuser table
Tracking messages by transaction log offsets
Handling lost or corrupt messages