SQLWithVJ

  🚫 SQL Server Configuration: “What NOT to Touch” A Practical DBA Checklist to Avoid Self-Inflicted Performance Problems SQL Server exposes dozens of configuration options. Some are powerful. Some are dangerous. And some are frequently misused , especially under performance pressure. This article compiles a battle-tested “what NOT to touch” checklist for SQL Server DBAs and performance engineers—with reasons , real risks , and safe alternatives . If you’ve ever seen performance “fixed” by clearing cache, restarting SQL Server, or disabling parallelism—you’ll recognize these immediately. Why This Checklist Matters Most SQL Server outages are not caused by hardware or bugs . They are caused by well-intentioned but harmful configuration changes . 🔑 Golden rule: If you don’t clearly understand what a setting fixes, don’t touch it. ❌ 1. Lightweight Pooling (Fiber Mode) What people change sp_configure 'lightweight pooling' Why this is danger...

In the world of SQL Server tuning, we spend a lot of time on index fragmentation, query plans, and memory allocation. But there is a "hidden parameter" that often dictates the ceiling of your performance: the disk subsystem. Even the most optimized query will crawl if it’s waiting on physical hardware to read or write data. If you want a truly high-performing SQL Server, you have to look beyond the code and into the hardware. Why Storage Matters So Much for SQL Server Performance? SQL Server is an I/O-intensive application . Even with plenty of RAM, SQL Server still relies heavily on disk operations for: Data file reads and writes Transaction log writes TempDB operations Backups and restores Index maintenance Checkpoints and crash recovery When disk I/O is slow, everything else slows down , regardless of how powerful your CPU or how optimized your queries are. 1. The Real-World Impact:  Latency vs.  IOPS vs. Throughput  To choose the righ...