Scheduling and Delivery Processor
SQL Server Reporting Services includes a Scheduling and Delivery Processor component to support scheduled operations and drive the delivery extensions used to push reports to e-mail inboxes or shared folder destinations. The Scheduling and Delivery Processor provides the following functionality:
Maintains a queue of events and notifications. In a scale-out deployment, the queue is shared across all of the report servers in the deployment.
Calls the Report Processor to execute reports, process subscriptions, or clear a cached report. All report processing that occurs as a result of a schedule event is performed by the Report Server Windows service rather than the Report Server Web service.
Calls the delivery extension that is specified in a subscription so that the report can be delivered.
Other aspects of a scheduling and delivery operation are handled by other components and services that work with the Scheduling and Delivery Processor. Specifically, the Scheduling and Delivery Processor runs in the Report Server Windows service and uses SQL Server Agent as a timer to generate scheduled events. The following list describes how scheduled operations work in a Reporting Services deployment:
A scheduled operation is defined when a user creates a schedule. The schedule defines a date and time that will be used to run a report, refresh a snapshot, or expire a cache.
The report server saves the schedule information in the report server database.
The report server creates a corresponding job in SQL Server Agent and runs it on the schedule information provided. The jobs are created through a stored procedure, using the existing open connection to the report server database.
SQL Server Agent runs the job on the date and time specified in the schedule. The job creates an event that is added to a queue maintained by Reporting Services.
The event causes a report or subscription process to occur. Events are processed when they are detected in the queue, and the report is processed or delivered accordingly.
Reporting Services maintains an event queue for all scheduled operations. It polls the queue at regular intervals to check for new events. By default, the queue is scanned at 10 second intervals. You can change the interval by modifying the PollingInterval, IsNotificationService, and IsEventService configuration settings in the RSReportServer.config file. For more information, see RSReportServer Configuration File.
The Scheduling and Delivery Processor requires that the Report Server Windows service and SQL Server Agent are started. The Schedule and Delivery Processing feature must be enabled through the SQL Server Surface Area Configuration tool. Both SQL Server Agent and the Report Server Windows service must running in order for scheduled operations to occur.
|You can use the Surface Area Configuration tool to stop scheduled operations on a temporary or permanent basis. The Scheduling and Delivery Processor is not extensible and has no configuration settings. You cannot change how it manages events and notifications. For more information about the Surface Area Configuration tool, see SQL Server Surface Area Configuration.|
Effects of Stopping the SQL Server Agent
Scheduled report processing uses SQL Server Agent by default. If you stop the service, no new processing requests are added to the queue unless you add them programmatically through the FireEvent method. When you restart the service, the jobs that create report processing requests are resumed. The report server does not try to recreate report processing jobs that might have occurred in the past, while SQL Server Agent was offline. If you stop SQL Server Agent for a week, all scheduled operations are lost for that week.
|The functionality that SQL Server Agent provides to Reporting Services can be replaced with custom code that uses the FireEvent method to add schedule events to the queue.|
Effects of Stopping the Report Server Windows Service
If you stop the Report Server Windows service, SQL Server Agent continues to add report processing requests to the queue. Status information from SQL Server Agent indicates that the job succeeded. However, because the Report Server Windows service is stopped, no report processing actually occurs. The requests will continue to accumulate in the queue until you restart the Report Server Windows service. Once you restart the Report Server Windows service, all report processing requests that are in the queue are processed in order.