When Page Prefetching Takes a Back Seat – Exploring Trace Flag 652 in SQL Server
Learn how a trace flag affects SQL Server reading from disk and where this might be a useful thing for you to enable.
2025-09-24
2,500 reads
SQL Server internal storage
2025-05-16
624 reads
2025-01-15
1,860 reads
What happens when we drop a column on a SQL Server table? Where's my space?
You have dropped a column and wondering why you haven't recovered any space? Let's take a look.
2024-08-01 (first published: 2024-04-26)
4,864 reads
Identify Tables With Dropped Columns
How easily can we find tables with dropped columns that need cleanup?
2024-06-07
2,561 reads
2024-04-10
456 reads
Understanding CRUD Operations on Tables with B-tree Indexes, Page-splits, and Fragmentation
Introduction Every DML transaction reads the data before it makes any changes. Not only during a SELECT query, but when you run any DML statement, insert, update, or delete, SQL Server first fetches a bunch of pages into the buffer pool locating the desired rows and changes them while synchronously writing to the transaction log […]
2021-05-10
8,487 reads
Understanding CRUD Operations Against Heaps and Forwarding Pointers
In this article, we examine how data changes are made against heaps.
2021-05-03
4,840 reads
Understanding the Internals of a Data Page
In Part 1 of this series, we examine the structure of data pages and how your tables are stored on these pages.
2021-04-13
20,377 reads
2020-06-26
645 reads
Blogs
T-SQL Tuesday #198–Change Detection
By Steve Jones
This month we have a new host, Meagan Longoria, who graciously agreed to help...
Redgate and Rome
By Steve Jones
I’m at the UK Redgate office today, meeting with senior leaders in all areas...
Quick Tip: Check Most DTU Expensive Queries in Azure SQL Database
Optimizing Azure SQL Database performance often begins with identifying the most resource-intensive queries. Understanding...
Forums
Creating a JSON Document IV
Comments posted to this topic are about the item Creating a JSON Document IV
Restoring Azure Key Vault Keys and Validating SQL Server TDE Recovery: Level 7 of the Stairway to TDE
By VishnuGupthanSQLPowershellDBA
Comments posted to this topic are about the item Restoring Azure Key Vault Keys...
Permissions Removal When Changing Object Schema
When the schema of an object is changed, SQL Server wipes out the previous...
Question of the Day
Creating a JSON Document IV
I have this data in a table called dbo.NFLTeams
TeamID TeamName City YearEstablished ------ -------- ---- --------------- 1 Cowboys Dallas 1960 2 Eagles Philadelphia 1933 3 Packers Green Bay 1919 4 Chiefs Kansas City 1960 5 49ers San Francisco 1946 6 Broncos Denver 1960 7 Seahawks Seattle 1976 8 Patriots New England 1960If I run this code, how many rows are returned?
SELECT YearEstablished, json_objectagg(city : TeamName) FROM dbo.NFLTeams GROUP BY YearEstablished;See possible answers