A new feature in SharePoint Server 2010, resource throttling provides options for monitoring and throttling server resources and large lists for Web applications. This enables you to control resource utilization during peak usage and prevent user activity from negatively affecting server performance.
Resource throttling can monitor such resources as CPU, Memory, and Wait Time, checking resources every 5 seconds. Throttling will begin after 3 unsuccessful checks. This throttling period will end after a successful check of the resources.
Note that during a period of active throttling, HTTP GET requests and Search Robot requests will generate a 503 error and will be logged in the event viewer and no new timer jobs will begin.
To enable resource throttling:
- On the General Settings Ribbon, select Resource Throttling.
- Enter values for the List View Threshold option. This limits queries within a list to guard against performance degradation with too many list items. In SharePoint Server 2010, a list can support up to 50 million items. Two thousand items in a view is the accepted performance limit in SharePoint Server 2010.If a list contains a large number of items, queries with too many results will be very slow. If a user attempts an action that would reach a throttle limit, a message appears listing alternative methods that will not affect performance.
- Allow or disallow object model override. This allows users with the appropriate permissions to programmatically override the List View Threshold setting for specific queries.
- Set the List View Threshold for auditors and administrators.
- Define the List View Lookup Threshold. The default of 8 generally works in new implementations. List view lookups can often go beyond six fields. In this event, you need to increase the limit.
- Define the List Unique Permission Threshold. This option is rarely changed.
- Turn Backward-Compatible Event Handlers on or off. By default, this is off. If you have a large amount of development work in SharePoint Server 2007 that leveraged event handlers for lists or libraries, you will want to turn this on. You should check with your developers if you are upgrading from SharePoint Server 2007.
- Configure HTTP Request Monitoring And Throttling. This changes the setting in IIS for all Web servers in the farm for this Web application.
- Define the Change Log constraints. Be careful not to reduce this too much because it will negatively affect servers that rely on history information for sites contained in the Web application.
- Click OK.