Isolate Performance Problems
Applies to: 
SQL Server
Azure SQL Database
Azure SQL Managed Instance
It is often more effective to use several Microsoft SQL Server or Microsoft Windows tools together to isolate database performance problems than to use one tool at a time. For example, the graphical Execution Plan feature, also called Showplan, helps you quickly recognize deadlocks in a single query. However, you can recognize some other performance problems more easily if you use the monitoring features of SQL Server and Windows together.
SQL Server Profiler can be used to monitor and troubleshoot Transact-SQL and application-related problems. System Monitor can be used to monitor hardware and other system-related problems.
You can monitor the following areas to troubleshoot problems:
SQL Server stored procedures or batches of Transact-SQL statements submitted by user applications.
User activity, such as blocking locks or deadlocks.
Hardware activity, such as disk usage.
Problems can include:
Application development errors involving incorrectly written Transact-SQL statements.
Hardware errors, such as disk- or network-related errors.
Excessive blocking due to an incorrectly designed database.
Tools for Common Performance Problems
Equally important is careful selection of the performance problem that you want each tool to monitor or tune. The tool and the utility depend on the type of performance problem you want to resolve.
The following topics describe a variety of monitoring and tuning tools and the problems they uncover.