Yes, Cardinality Estimation Keeps Changing After SQL Server 2014.
About 10 years ago, Microsoft made changes to the Cardinality Estimator (CE) which caused some problems for SQL […]
Execution plans
Does Your GROUP BY Order Matter?
Sometimes when you do GROUP BY, the order of the columns does matter. For example, these two SELECT […]
What Happens When Multiple Queries Compile at Once?
An interesting question came in on PollGab. DBAmusing asked: If a query takes 5-7s to calculate the execution […]
Plansplaining, part 20. SQL Graph (part 1)
The post Plansplaining, part 20. SQL Graph (part 1) appeared first on SQLServerCentral.
Explore Natively Compiled SQL Server Stored Procedure Execution Plans
The post Explore Natively Compiled SQL Server Stored Procedure Execution Plans appeared first on SQLServerCentral.
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 […]
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 […]