Performance Killers in MSSQL

• Frequent recompilation of execution plans
• Inaccurate statistics
• Excessive use or improper configuration of tempdb
• Excessive blocking and deadlocks
• Excessive fragmentation
• Improper use of cursors
• Improper configuration of the database log
• Non-reusable execution plans
• Non-set-based operations, usually T-SQL cursors
• Poor database design
• Poor query design
• Poor indexing
• Poor execution plans, usually caused by parameter sniffing