12 SQL Stored Procedure Optimization Strategies

🚀 12 Rules for High-Performance SQL Stored Procedures When it comes to backend engineering, database bottlenecks can be considered "silent killers" of your application's performance. After years of evaluating execution plans, I’ve identified these twelve optimization strategies as having the most significant impact on improving performance. The basics: 1. SET NOCOUNT ON: Prevent unnecessary "rows affected" messages from communicating on the network. 2. Specify Columns: Never SELECT *, only retrieve the columns you actually need to minimize I/O. 3. Schema Qualification: Use [dbo].[Table]. This eliminates the need for the engine to look through all the schemas during compilation. 4. IF EXISTS > COUNT(): Do not scan the entire table to find out whether or not there is a record. The Architecture Level: 5. Write SARGable Queries: Use WHERE clauses that can make use of an index on the referenced column. Do not create functions on that column name. For example, instead of using the function YEAR(Date) = 2024; you should write the same logic as Date >= '2024-01-01'. 6. Lean Transactions: The longer a transaction is, the more likely you will run into deadlocks or blocks. 7. Prefer UNION ALL to UNION: Do not use the expensive internal Sort/Distinct unless you have to have unique rows. 8. Avoid Scalar Functions: They are just like loops; use Inline Table-Valued Functions instead of scalars to allow for a better execution plan. Pro-Level Tuning: 9. Table Vars vs. Temp Tables: Use @Table for small datasets ($<1000$ rows). They lead to fewer recompiles but lack statistics (the optimizer assumes 1 row). Use #Temp for large datasets or complex joins. They support full statistics and indexing, allowing the engine to generate an accurate execution plan. 10. Manage Parameter Sniffing: Use local variables to prevent the engine from locking into a sub-optimal plan based on one specific input. 11. Set-Based Logic: Ditch the Cursors. SQL is built for sets, not row-by-row looping.. 12. Never use dynamic SQL: it presents significant security vulnerabilities and will also reduce the ability for an execution plan to be reused. #SQLServer #DatabaseOptimization #BackendEngineering #DotNet #CleanCode #ProgrammingTips #SoftwareArchitecture

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