A Fine Slice Of SQL Server
Pat Wright wraps up another T-SQL Tuesday:
Thank you all for submitting to T-SQL Tuesday. I have summaries from each blog below, and I added my own comments. I’ve written about this topic in the SSC editorial that is coming out this Saturday. I’ll link back to it on this blog post, but you’ll find it here when it releases on Saturday.
Click through for posts from five participants this time around.
Leave a CommentJonathan Stewart has a new open-source tool:
Wait, what? Didn’t you already build one of these?
I built a data generator, yes. But when I realized what profiling the data could open up, the ideas just kept coming. “With this data I could do this.” Then something else. Then something else.
The generator was only half the picture. Before I could make data behave the way I needed, I had to understand how it behaved in the first place.
Your schema tells you column names and types. It doesn’t tell you that December might bring in nearly three times February’s orders, that a small group of customers might place most of them, or that a field’s null rate might jump between two captures.
Click through for the intro article and check out the GitHub repo as well as a playground where you can try it in your browser.
Leave a CommentHugo Kornelis digs into another index variant:
Support for the vector data type, vector indexes, and vector search, was added as a preview feature in SQL Server 2025 and in Azure SQL Database. In the latter, the feature has then been developed further, and moved out of preview.
There have been significant changes between the original implementation, that is still available in SQL Server 2025 (as of CU9), and the current (mid October 2026) implementation in Azure SQL Database. These differences affect the available features, the syntax to use for some features, and the internals. Especially the latter is important for those who already created vector indexes with the original implementation on Azure SQL Database. Because the new version uses a different structure, these users are recommended to migrate from that earlier version to the new version. Click this link for more information.
In this post, I will look at both the original implementation, as still available in SQL Server 2025, and at the current implementation in Azure SQL Database, pointing out similarities and differences where needed.
Click through for a theoretical explanation of when vector operations are relevant as well as how SQL Server and Azure SQL DB actually store this information. Hugo may apologize for how long the post is, but on his behalf, I highly recommend giving it a read.
Leave a CommentThe latest SQL Server Management Studio 22 update (22.11.0) seems to have caused some issues, including nuking the connection history, as per Brent Ozar’s post.
I figured it might be useful to have a way to backup SSMS 22’s connection history before an update, and then restore it in case of similar issues.
Click through for that process.
Leave a CommentChris Webb explains the paradox:
As a follow-on from last week’s post about the new ApproximateDistinctCount function in DAX, I want to share something I found out from my recent testing for this function: ApproximateDistinctCount is sometimes slower than DistinctCount. This sounds counter-intuitive, right? After all ApproximateDistinctCount is a performance optimisation for the sometimes slow, expensive DistinctCount function. But it turns out that there are certain engine optimisations for DistinctCount that can’t be replicated for ApproximateDistinctCount which mean that for low-cardinality columns using DistinctCount can be faster.
Click through for an example.
Leave a CommentWarwick Rudd continues a series:
In Part 1 we built somewhere safe to put the backups: a storage account with a delete lock and a container with a time-based retention policy.
The next problem is getting SQL Server to write to it without giving it a password. That’s what the Managed Identity is for. The VM gets an identity in Microsoft Entra ID, SQL Server uses it to authenticate to storage, and there’s no SAS token or storage key anywhere to steal, rotate or forget about.
There are a few moving parts to get there, and most of the time spent on this is in Entra ID and networking rather than SQL Server.
Read on to see what needs to happen.
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