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
6,455 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)
9,044 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
159 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)
5,368 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)
6,517 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
T-SQL Tuesday #181: A Technology Present
By Steve Jones
It’s the last T-SQL Tuesday of the year, and it’s amazing to think we’ve...
Trace Flag 3625 Follow Up
By Patrick
Several months ago, I discussed my customer’s intention to enable trace flag 3625. Since...
Top 5 Advanced SQL Courses for 2025 (Must-Know)
Want to seriously boost your data skills? Mastering advanced SQL is the key, whether...
Forums
Date data type not recognized with oledb type provider
Hello, We recently made the following reservation working with VS2022 combined with the SSIS...
The Hash Join III
Comments posted to this topic are about the item The Hash Join III
Continuous Learning
Comments posted to this topic are about the item Continuous Learning
Question of the Day
The Hash Join III
In a hash join, if all the build input does not fit in memory, what type of hash join is this?
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