Cardinality Estimation for a Predicate on a COUNT Expression
Paul White takes you on an optimizer journey, exploring how SQL Server comes up with cardinality estimates for COUNT queries.
2017-05-17
3,222 reads
Cardinality Estimates
Bad Cardinality Estimates from SSMS Plans – Redux
Aaron Bertrand shares some insight about early changes to Plan Explorer that help to provide you with the most accurate information we can.
2016-04-04
2,780 reads
Fixing Gatekeeper Row Cardinality Estimate Issues
The Query Optimiser needs a good estimate of the number of rows likely to be returned by each physical operator in order to select the best query plan from the most likely alternatives. Sometimes these estimates can go so wildly wrong as to result in a very slow query. Joe Sack shows how it can happen with SQL Queries on a data warehouse with a star schema.
2012-12-10
1,163 reads
Blogs
SQL Server is Slow, part 3 of 4
By Kevin3NF
In parts 1 and 2 of this series, we’ve gathered info and done the...
AI Model Size, Parameters and Download
By Steve Jones
At SQL Saturday Boston 2025, I gave a presentation on local LLMs and there...
Expanding Your DBA Horizons: Installing PostgreSQL in a Home Lab
By gbargsley
Are you diversifying your DBA skillset? My recent job search made one thing clear:...
Forums
caught off guard by some greek lettering in a warehouse feed
Hi we run 2019 standard. Our warehouse's ssis based etl is klunky but so...
Unlocking High-Concurrency Inserts in SQL Server with OPTIMIZE_FOR_SEQUENTIAL_KEY
Comments posted to this topic are about the item Unlocking High-Concurrency Inserts in SQL...
Vector Datatype
Comments posted to this topic are about the item Vector Datatype
Question of the Day
Vector Datatype
The new Vector datatype in SQL Server 2025 is a binary type that has a few parameters. What parameters are required?
See possible answers