A Little More About Isolation Levels In SQL Server скачать в хорошем качестве

A Little More About Isolation Levels In SQL Server

In this video, I delve into the complexities of SQL Server isolation levels, focusing on why they often require repeated explanations. I start by addressing common misconceptions and pitfalls associated with using no lock hints and switching between read committed and read committed snapshot isolation (RCSI). While RCSI isn't perfect, it significantly reduces blocking and deadlocking issues in many scenarios, making it a safer choice for most SQL Server workloads. Throughout the video, I illustrate how certain query patterns can lead to perceived race conditions under both pessimistic and optimistic isolation levels, emphasizing that read committed's promises are often overestimated. By walking through practical examples, such as updating table aliases with exists checks, I demonstrate how these issues manifest differently under RCSI compared to traditional read committed isolation, ultimately guiding viewers on when and why to consider switching to an optimistic isolation level for improved concurrency and performance. CHAPTERS 00:00:00 - Introduction 00:01:25 - No Lock Hints and Bad Data 00:02:48 - Read Committed vs Snapshot Isolation 00:04:36 - Race Conditions Under Pessimistic Level 00:07:46 - Query Patterns Causing Issues 00:10:52 - Optimistic Isolation Level Examples 00:13:08 - Blocking and Versioning 00:16:03 - Benefits of RCSI 00:18:15 - Conclusion ━━━━━━━━━━━━━━━━━━━━━━━━━━ 📚 TRAINING & COURSES ━━━━━━━━━━━━━━━━━━━━━━━━━━ Get AI-Ready With Erik https://training.erikdarling.com/get-... SQL Server Performance Engineering Course https://training.erikdarling.com/sql-... Learn T-SQL with Erik https://training.erikdarling.com/lear... Everything Bundle: https://training.erikdarling.com/?cou... ━━━━━━━━━━━━━━━━━━━━━━━━━━ 🛠️ CONSULTING & SERVICES ━━━━━━━━━━━━━━━━━━━━━━━━━━ Need SQL Server performance help? https://training.erikdarling.com/sqlc... ━━━━━━━━━━━━━━━━━━━━━━━━━━ 💬 CONNECT ━━━━━━━━━━━━━━━━━━━━━━━━━━ Ask questions at Office Hours https://erikdarling.com/officehours/ Become a channel member    / @erikdarlingdata   ━━━━━━━━━━━━━━━━━━━━━━━━━━