Configuring Spotlight Cache schedules efficiently optimizes columnstore index maintenance in SQL Server. Follow these steps:
Understanding Spotlight Cache
Spotlight Cache holds frequently accessed segments of columnstore indexes in memory. A properly scheduled refresh ensures optimal query performance by keeping relevant segments loaded.
Prerequisites
- SQL Server Edition: Enterprise Edition is required.
- Permissions: You need ALTER SERVER STATE permission.
- Analysis: Identify peak workload periods when cached segments benefit performance most.
- Disk Space: Ensure sufficient space in the default SQL Server data directory.
Configuration Steps
- Connect to SQL Server:
Open SQL Server Management Studio (SSMS) and connect to your target instance.
- Navigate to Server Properties:
Right-click the server instance name in Object Explorer and select Properties.
- Access Memory Settings:
Go to the Memory section in the left-hand pane.
- Configure Global Schedule (Default):
- Locate the "Enable Columnstore Cache Management" option. Ensure it is checked.
- Find the "Columnstore Cache Refresh Schedule" parameter.
- Click the ellipsis (...) button to open the schedule editor.
- Define Schedule Settings:
- Set "Schedule type" to Recurring.
- Choose the Frequency (typically Daily).
- Set the Time to occur during predictable low-activity periods (e.g., outside business hours).
- Verify the Start Date and End Date (usually leave as "No end date").
- Click OK to save the schedule.
- Apply & Save:
Click OK on the Server Properties window to apply the new global Spotlight Cache schedule. No instance restart is required.
Verification & Best Practices
- Confirm Status: Execute
SELECT name, is_cache_enabled FROM *to verify caching is active per database. - Monitor Performance: Use Performance Monitor or query *_store_row_groups to track cache hit ratios and segment usage after enabling.
- Schedule Timing: Run the refresh during consistent low-load windows. Avoid peaks.
- Adjust Memory: If system memory is constrained, evaluate resource consumption (e.g., via *_os_memory_clerks). Tune overall memory allocations if needed.
- Review Logs: Check SQL Server logs for Spotlight Cache-related messages.
