In database operation and maintenance, a DBA often encounters a more urgent problem, that is, a sudden CPU full (CPU utilization reaches 100%), resulting in business stagnation. DBAs are not necessarily very familiar with business implementation logic, nor can they control changes from applications or load changes. Therefore, when the CPU is full, it is often possible to start the investigation from the back-end database, trace back to the specific SQL, and finally locate the business layer. Here we summarize the specific approach to this problem.