Is it in principle possible for the CPU to be the bottleneck on a SQL Server if the Performance Counter Processor:Processor Time is constantly under 30% on all cores? Or does low Processor Time automatically allow me to rule out the CPU as a potential trouble source?
I am asking this because SQL Nexus lists CPU as the top bottleneck on a server with low Processor Time values.
Best Answer
In cases where there are a lot of synchronous operations in a query the cpu can become the bottle neck even when the cpu is reporting to have cycles to spare. There's only so much multi-threading that can happen. As cpu core count continues to increase the more you'll likely see this scenario. About the only thing you can do is get faster CPU cores or look into what sort of optimization can be done to the query/database.