There was a problem time frame of 30 mins (22:00 to 22:30) during which queries had performance issues - bad execution plans, which led to high CPU. That's what monitoring tool shows:
Checking other performance metrics for this time frame, they show a 30 min gap
Batch Requests / sec:
Basically, all SQL Server related performance metrics (Batch Requests / sec, Memory Grants, Granted Workspace Memory, etc.) are missing for a problem time frame, while machine metrics (CPU, memory, network, disk etc.) are present
Why could this be ?