Check SQL Server Cardinality Estimation Issues in 45 Seconds. The "45 Seconds DBA Series". Part 12
Before we dive into today's topic, if you missed my previous post you can take a look at Check Execution Plans in 45 Seconds . 👉 If you found this deep-dive helpful, feel free to check out the ads—your support helps me keep creating high-quality SQL Server content for the community. Check SQL Server Cardinality Estimation Issues in 45 Seconds Execution Engine Deep Dive | Part 12 In this post, I will show you how to identify the silent killer of performance: the "Estimate vs Actual" row gap. Mastering Cardinality Estimation is the difference between a sub-second response and a server-wide timeout. 🧠 TL;DR BOX ✔️ Cardinality Estimation (CE) is the Optimizer's prediction of how many rows a query will process. ✔️ A massive discrepancy between Estimated and Actual rows leads to sub-optimal join choices and memory grant spills. ✔️ Primary culpri...