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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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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

Before we dive into today's topic, if you missed my previous post you can take a look at Check Parameter Sniffing in 45 Seconds. Execution Engine | Part 15 . 👉 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. SQL Server: Why Your Queries Return Wrong Results (And You Don’t Know It) Silent Killers | Part 16 Performance is nothing without accuracy. Stop trusting your reports blindly. Performance is irrelevant if the data is wrong. In this post, I’ll expose the silent killers that cause SQL Server to return incorrect results without throwing a single error—a nightmare for any Senior DBA. 🧠 TL;DR BOX ✔️ NOT IN + NULL: If your subquery contains a single NULL, your entire result set becomes empty 💣 ✔️ NOLOCK (Dirty Reads): Can cau...
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