22-25 April 2026 
X-Raying Schema Operations: Adding and Removing Columns
2025TL; DR
Do you need to handle schema changes?
Maybe create a new column on a busy table? Maybe drop a column to recover space.
Do you know the pitfalls and what you should take into account?
It's easy to halt a system when we aren't doing things in the best way.
Come and learn important details that will allow you to plan these actions, in the best way possible, before running your scripts!
Session Details
As database developers and/or administrators, we often encounter the need to make schema changes to tables. These changes involve various operations, such as adding or removing columns.
Understanding the inner workings of these operations may be crucial. Why are some changes quick and seamless, while others can significantly impact system performance?
In this session, we'll delve into SQL Server internals to explore the processes involved in adding and removing columns. We'll examine the intricacies of these operations, including their utilization of the transaction log, the locking system, and space management. This exploration will unravel their impact (or lack thereof) on system resources and performance.
Is adding a new column always a slow and a blocking operation? And what about dropping a column? Will this single action immediately reclaim the used space? Let's explore these and other questions together.
By gaining insight into these specific examples, you will be better equipped to manage similar schema changes effectively in your database environments.
Understanding the inner workings of these operations may be crucial. Why are some changes quick and seamless, while others can significantly impact system performance?
In this session, we'll delve into SQL Server internals to explore the processes involved in adding and removing columns. We'll examine the intricacies of these operations, including their utilization of the transaction log, the locking system, and space management. This exploration will unravel their impact (or lack thereof) on system resources and performance.
Is adding a new column always a slow and a blocking operation? And what about dropping a column? Will this single action immediately reclaim the used space? Let's explore these and other questions together.
By gaining insight into these specific examples, you will be better equipped to manage similar schema changes effectively in your database environments.
3 things you'll get out of this session
Understand what happens when we do some type of schema changes and how that can impact the system.
We will see if/how you can reduce that impact.
Make attendees think about these types of changes and test them before going live.
Speakers
Cláudio Silva's other proposed sessions for 2026
Performance of a T-SQL query - The mystery, the investigation and the root cause! - 2026
Accelerating Query Store data analysis with sp_QuickieStore - 2026
dbatools - Wheel of Fortune - 2026
Cláudio Silva's previous sessions
Let me show you why data types still matter
Selecting the right data types is still important. Let's see some examples of why!
Writing T-SQL code for the engine, not for you "more demos" by popular demand
Often because of how quickly we want to write a T-SQL query we create more extra work for the engine.
People underestimate the power of rewriting a T-SQL query, but in the right cases, it will provide better performance.
Let's look at some scenarios where this is true!