SQL Executive has a scheduling engine that controls scheduled replication tasks and is used to implement replicated data transfer. This scheduling engine has three subsystems: the log reader process, the distribution process, and the synchronization process. Together they provide the functionality that, administered through SQL Enterprise Manager, allows you to set the frequency of each replication task. For example, you could set up replication so that the publisher's log is continuously read, transactions are distributed to subscribers every ten minutes, and initial synchronization events occur every night at midnight. For more information on these processes, see Replication Components, earlier in this chapter.
SQL Executive maintains a task list, a task queue, and a task history that can be useful for troubleshooting replication. These can be viewed and managed by using SQL Enterprise Manager. For information on monitoring scheduled tasks, see Chapter 16, Scheduling Tasks.
Events in the task history can also be written to the Windows NT application log¾if the task is set to use Windows NT logging¾and can be viewed by using Event Viewer. For information on using Event Viewer, see your documentation for Windows NT.
SQL Executive also has an alerts engine that provides an easy way to set alerts on replication events. When the event occurs, SQL Executive responds automatically, either by executing a task that you have defined or by sending an email and/or a pager message to an operator you have specified. For information on setting up alerts for replication, see Chapter 17, Managing Alerts.