SQL Window Functions Series: LAG() and LEAD()
Dive deep into the powerful SQL window functions, LAG() and LEAD(). Explore their intricacies, discover real-world examples, and avoid common pitfalls.
2023-12-11
9,660 reads
Performance Tuning
Analyze and Tune SQL Server Statistics
Over the years, SQL Server Statistics have been discussed in countless blog posts, articles, and presentations, and I believe that they will remain a core topic for a while when speaking about performance. Why is that?
2023-10-04
SQL Server Execution Plan Issues when using TOP Clause and Various Parameters
A query is sometimes super fast and sometimes very slow. One of the main reasons for this problem is Parameter Sniffing. There are several approaches to addressing the Parameter Sniffing issue and this article discusses effective methods for handling Parameter Sniffing in SELECT statements containing a TOP clause.
2023-09-18
Comparing Two Execution Plans
This is a short look at a technique that I discovered recently in Management Studio (SSMS). The technique is to compare two graphical execution plans in the tool to understand what they are doing and how two different queries might affect a particular system, both with the image and with the properties' data behind the […]
2023-11-24 (first published: 2021-03-30)
10,729 reads
SQL Server SET STATISTICS IO ON Deep Dive
In this article we look at how to interpret and use the results of STATISTICS IO when tuning SQL Server queries.
2021-02-17
Digging Into Internals
There are plenty of experts that look to teach you about query tuning and the internals of query execution in SQL Server.
2020-07-18
164 reads
A simple use case for Columnstore Indexes in SQL Server
In this article we look at different use cases for columnstore indexes like when performing SQL Server count * queries.
2020-01-17
Optimize Your SQL by Reformulating the Spec
As SQL developers, we tend to think of performance tuning in terms of crafting the best table indices, avoiding scalar and table valued functions, and analyzing query plans (among other things). But sometimes going back to the spec and applying some properties of elementary math can be the best way to begin to improve performance of SQL queries which implement mathematical formulas. This article is a case study of how I used this technique to optimize my SQL implementation of the Inverse Simpson Index.
2021-05-07 (first published: 2019-09-12)
5,394 reads
The Basics - Level 1 of the Stairway to Query Store
Introduction Instead of going straight into the topic of the Query Store, I would like to start this Stairway Series by mentioning a few performance tuning scenarios that are very common to production DBAs. I think most of us have been in one of these situations at some time: An application experiencing slowness after a […]
2020-10-07 (first published: 2019-05-13)
6,898 reads
IGNORE_DUP_KEY slower on clustered indexes
The IGNORE_DUP_KEY option for unique indexes specifies how SQL Server responds to an attempt to INSERT duplicate values: It only applies to tables (not views) and only to inserts. Any insert portion of a MERGE statement ignores any IGNORE_DUP_KEY index setting.
2019-04-05
Blogs
“We love to debate minutiae”
By Brian Kelley
I am guilty as charged. The quote was in reference to how people argue...
Advice I Like: Knots
By Steve Jones
Learn how to tie a bowline knot. Practice in the dark. With one hand....
Shifting Mindsets: Why FinOps is Essential for Cloud Efficiency
By HeyMo0sh
As a DevOps practitioner, I’ve always focused on performance, scalability, and automation. But as...
Forums
Windows logins for users migrated from DomainA to DomainB
Hi, I have a SQL Server instance where users connect to via Windows Authentication,...
Multiple Deployment Processes
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How to Use sqlpackage to Detect Schema Drift Between Azure SQL Databases
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Question of the Day
Upgrading Admin Queries
I have a query from a former DBA that we run on SQL Server 2025 to check on database metadata. This query references sys.sysaltfiles. I want to refactor this code to be more modern. Which DMV should I reference instead?
See possible answers