Parameter Sniffing in SQL

Parameter sniffing in SQL Server eliminates the need to recompile query plans, thereby saving CPU cycles and avoiding plan pollution. While this feature can optimize query performance, it can also lead to unexpected issues if not managed correctly. In this session, we will explore the concept of parameter sniffing, how SQL Server optimizes queries based on parameter values, and common scenarios where it can cause performance problems. We'll discuss various practical strategies to mitigate these issues, including plan guides, Parameter Sensitive Plan optimization, and query hints like OPTIMIZE FOR and OPTION (RECOMPILE), which can now be added to the Query Store without rewriting the code. By the end of this session, you'll have a thorough understanding of parameter sniffing and the techniques to optimize your SQL Server queries for better performance.