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Why Cursors Kill Performance (and When They Don’t), The "45 Seconds DBA Series" | Part 21

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Before we dive into today's topic, if you missed my previous post you can take a look at The Dangerous Truth About Scalar Functions in 45 Seconds, The "45 Seconds DBA Series" | Part 20 . 👉 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. Why Cursors Kill Performance (and When They Don’t) The "45 Seconds DBA Series" | Part 21 In this post, I’ll expose why T-SQL cursors are often the primary cause of CPU spikes and blocking chains. Master the set-based mindset to unlock massive scalability! 🧠 TL;DR BOX ✔️ RBAR (Row-By-Agonizing-Row): Cursors execute procedural logic, destroying the power of the set-based optimizer. 💣 ✔️ High Overhead: Context switching between the engine and the cursor memory destroys throughpu...
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The Dangerous Truth About Scalar Functions in 45 Seconds, The "45 Seconds DBA Series" | Part 20

Before we dive into today's topic, if you missed my previous post you can take a look at SSMS 22.6.0 Is OUT! Review & Test! . 👉 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. The Dangerous Truth About Scalar Functions in 45 Seconds The "45 Seconds DBA Series" | Part 20 Scalar UDFs are the silent killers of SQL Server performance. In this post, I will reveal why they hide their true cost and how they turn a fast query into a row-by-row disaster. 🧠 TL;DR ✔️ Scalar UDFs force RBAR (Row-By-Agonizing-Row) execution, bypassing the set-based power of the optimizer. 💣 ✔️ Inhibits Parallelism: Traditional scalar functions force your entire query to run on a single thread. 🧵 ✔️ Hidden Costs: Execution plans ofte...
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SSMS 22.6.0 Is OUT! Review & Test!

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Before we dive into today's topic, if you missed my previous post you can take a look at Why NOLOCK Can Corrupt Your Logic 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. SSMS 22.6.0 Is OUT! Database DevOps, Better Diagnostics, Security Fixes, Entra Authentication, and Stability Improvements for Serious SQL Server Professionals. 🧠 TL;DR BOX ✔️ SSMS 22.6.0 introduces Database DevOps workload preview and improved Entra authentication support 🚀 ✔️ Results Grid now shows column data types directly in tooltips for faster diagnostics ⚡ ✔️ Multiple GitHub Copilot, Object Explorer, Query Editor, and SQL Agent bugs were fixed 💣 ✔️ Updated MSODBCSQL 18.6.2.1 and Visual Studio 18.6.0 improve stability and co...
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Why NOLOCK Can Corrupt Your Logic in 45 Seconds, The "45 Seconds DBA Series" | Part 19

Before we dive into today's topic, if you missed my previous post you can take a look at The Hidden Cost of Implicit Conversions 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. Why NOLOCK Can Corrupt Your Logic in 45 Seconds The "45 Seconds DBA Series" | Part 19 In this post, I’ll show you how the (NOLOCK) hint can silently double-count or skip records entirely in your reports. Don't risk your data integrity for a false sense of speed! 🧠 TL;DR ✔️ NOLOCK allows dirty reads of uncommitted, potentially rolled-back data 💣 ✔️ Allocation Scans can cause rows to be skipped or read twice during page splits 🔄 ✔️ RCSI is the professional alternative for non-blocking read consistency 🚀...
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The Hidden Cost of Implicit Conversions in 45 Seconds, The "45 Seconds DBA Series" | Part 18

Before we dive into today's topic, if you missed my previous post you can take a look at Check SQL Server TVP Join Problems in 45 Seconds Bad Estimates, TempDB Spills, and Parameter Sniffing | Part 17 . 👉 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. The Hidden Cost of Implicit Conversions in 45 Seconds The "45 Seconds DBA Series" | Part 18 💣 ➔ ⚡ ➔ 🚀 Implicit conversions are silent performance killers that turn ultra-fast Index Seeks into agonizingly slow Index Scans. In this post, I will show you how to spot them in under 45 seconds and reclaim your CPU cycles! 🧠 TL;DR BOX ✔️ SARGability Murder: Implicit conversions prevent SQL Server from using index seeks efficiently. 💣 ✔️ CPU Overhead: Converting every row in a table durin...
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Check SQL Server TVP Join Problems in 45 Seconds ...Bad Estimates, TempDB Spills, and Parameter Sniffing | Part 17

Before we dive into today's topic, if you missed my previous post you can take a look at SQL Server: Why Your SQL Server Queries Return Wrong Results (And You Don’t Know It). Silent Killes. The "45 Seconds DBA Series" | Part 16 . 👉 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 TVP Join Problems in 45 Seconds Bad Estimates, TempDB Spills, and Parameter Sniffing | Part 17 In this post, you will learn why joining Table-Valued Parameters (TVP) can cripple your performance with hidden TempDB spills and how to fix it using a robust production-ready pattern. 🧠 TL;DR BOX ✔️ Statistical Blindness: TVPs lack distribution statistics, forcing the Optimizer to make fixed cardinality guesses. 💣 ✔️ Memory Disaster: Underestimated row counts lead to insufficie...
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