What’s Faster: IN or OR? Columnstore Edition
Pinal Dave recently ignited a storm of controversy when he quizzed readers about which one of these would […]
Execution plans
This Week, Fundamentals of Query Tuning Classes are Free!
Every weekday during the month of October, one of the modules from my Fundamentals classes will be absolutely […]
Estimated and Actual Plans Can Have Different Shapes.
A reader posted a question for Office Hours: Hi Brent, What is your take on Hugo Kornelis’s explanation […]
SQL Server Pop Quiz: A Key Lookup Without the Index
How do we get this to show up in an execution plan: Without having an index seek or […]
I Wish SQL Server Warned About Hard-Coded Estimates.
I wish we got a yellow bang on execution plans when SQL Server was making up an estimate […]
SQL Server 2022 Tells You Why A Query Can’t Go ...
Until 2022, when a query couldn’t go parallel, all we got was a really cryptic note in the […]
How to troubleshoot and fix PostgreSQL performance issues
PostgreSQL is a popular database that is used by many applications. It’s been in active development for […]
“Index Seek” Doesn’t Mean Much.
When you see “index seek” on an execution plan, that doesn’t mean SQL Server is jumping to exactly […]
5 Ways to Measure a Query
In my free How to Think Like the Engine class, we start out by measuring query performance using […]
What Is a Cost-Based Optimizer?
When you execute a query, the database server has to figure out things like: Which table to process […]
“I’m getting index seeks. Why are my row estimates still ...
If you’ve got good indexes to support your query, and statistics to help SQL Server guess how many […]
What’s the Buggiest Feature in SQL Server?
Not the one you like the least, or the one that requires the most work. What’s the one […]
Execution Plans Don’t Have the Yellow Bang They Really Need.
When SQL Server is purely making an estimate up out of thin air, with no freakin’ idea what […]