SQL Server Performance

When to Use

• A query that used to be fast is now slow
• Reading execution plans to find bottlenecks
• Choosing between index strategies (clustered, covering, filtered)
• Diagnosing locking, blocking, or deadlocks
• Writing bulk INSERT/UPDATE/DELETE that won't bloat the transaction log
• Fixing parameter sniffing in stored procedures
• Deciding between temp tables and table variables
• Analyzing wait statistics to identify resource bottlenecks

When NOT to use: application schema design (table design, naming conventions, access control), backup/restore strategies, high availability configuration, or replication setup.

Diagnostic Flowchart