Create, modify, and delete snapshots in report history
Report history is a collection of report snapshots. You can maintain report history by adding and deleting snapshots, or by modifying properties that affect report history storage. You can create report history manually or on a schedule.
To create report history, your role assignment must include the "Manage report history" task. To view report history, your role assignment must include the "View reports" task. Report history is available to all users who have access to the report. You can't selectively enable or disable report history for a subset of users.
You can identify snapshots in report history by the date and time that they were created. The date and time is based on when the query executed.
Create snapshots in report history
Snapshots can be created manually or at scheduled intervals for any report that can run unattended. To run unattended, the report must use stored credentials or no credentials at all. Furthermore, if the report uses parameters, you must specify default values to use when the report runs. You can specify stored credentials and parameter values in the property pages for the report. For more information, see Parameters properties page (Report Manager).
When you create a report snapshot, the following elements are stored along with the report snapshot in the report server database:
The result set, which includes the data in the report, retrieved through the credentials specified in the Data Sources properties page of the report.
The underlying report definition, as it exists at the time the snapshot was created. If the report definition is modified after the snapshot is generated, those changes aren't reflected in the snapshot.
Parameter values that are used to obtain or filter the result set.
Embedded resources, such as images. External resources that are linked to a report aren't stored with the report snapshot.
Settings determine the ways in which report history can be created and the number of report snapshots that can be stored.
If a report produces an error, a snapshot isn't created. Reports that produce warnings, yet still run, can be used to generate snapshots.
Modify properties and delete report history
Once a report snapshot exists, you can't modify it. However, you can modify properties in a way that deletes report history.
Report history can be deleted in the following ways:
Manually delete snapshots singly or in groups.
You can delete snapshots from the History page in Report Manager. Navigate to the report, select History, select the checkbox next to the snapshots that you want to delete, and then select Delete.
Lower the report history limit to reduce the number of snapshots that are stored. The report history limit can be set for the report server or for specific reports. When the limit is lowered, the oldest snapshots are deleted from history.
You can't delete all report history stored on a report server in a bulk operation.
Report history is also deleted when you delete a report. For example, if you delete a monthly sales report because you're replacing it with a newer version, all report history that is associated with the report is also deleted. However, if you move a report, all report history moves with it.