Grooming is the process of deleting metrics stored in the repository that are older than a given date and time, this process is important because it optimizes the performance of processes such as data collection.

In SQL Workload Analysis you can set your grooming schedule by following these steps: 

1. Open the file <install-dir>\SQLWA\etc\mq\schedule.xml in a Notepad or any other editor. 
   
    
2. Look for the line that specifies the purge schedule in a Standard Cron Format (Line 19).
   
3. Change the number 1 to your preferred time value. The new value should be in a 24-hour format.
   
4. Restart the SWA services (IDERA Collector Services and IDERA Framework GUI service).

SQL Workload Analysis makes SQL Server performance tuning easy.