Posts

This is a post in the SQL Interview series. These aren’t trick or gotcha questions, they’re just questions designed to scope out a candidate’s knowledge around SQL Server and Azure SQL Database.

Section: Administration Level: Intro

Question:

You are restoring a database backup. The restore finished reading pages 10 minutes ago, but the database still shows that it is restoring.

Can you speed up the restoring phase by restarting the server? If so, should you do that? If not, why not?

2026-01-14

When people hear the phrase real-time, their minds often jump straight to sub-second response. They imagine dashboards updating instantly or transactions being analyzed faster than the blink of an eye. But in reality, not every scenario demands that level of speed — and chasing sub-second performance everywhere can actually be counterproductive.

It’s helpful to think about real-time in classes of latency. At the extreme, you have sub-second responses — critical for areas like algorithmic trading, where even a few milliseconds can cost millions. Then there are scenarios where a response in a few seconds is perfectly adequate — for example, fraud detection. If you can flag a suspicious credit card transaction within two or three seconds, that’s usually enough to stop the transaction before it clears. And then there are other cases where even minutes are fine. Think about a customer experience dashboard in a call center — if the screen refreshes every minute or two, that still feels live enough to be useful.

2026-01-13

This is a post in the SQL Interview series. These aren’t trick or gotcha questions, they’re just questions designed to scope out a candidate’s knowledge around SQL Server and Azure SQL Database.

Section: Administration Level: Intro

Question:

You have a database configured for simple recovery model. You notice that the transaction log is still increasing in size.

What could cause this?

Answer:

Even in the Simple recovery model, it is quite normal to see the transaction log file grow. That does not necessarily mean it’s stuck or misconfigured.

2026-01-12

When we talk about real-time, it’s worth asking: why does it matter so much? The answer is that in many situations, timing is everything. Traditional business reports are incredibly valuable, but they often arrive hours or days after the fact.

By the time you’ve spotted the issue, the opportunity to act has already passed.

Take fraud detection as an example. If a customer’s credit card is being misused, you can’t afford to wait until the next daily reconciliation. By then, dozens of fraudulent purchases might have gone through. Real-time intelligence means the system can detect unusual patterns on the spot and stop the fraud before it escalates.

2026-01-11

This is a post in the SQL Interview series. These aren’t trick or gotcha questions, they’re just questions designed to scope out a candidate’s knowledge around SQL Server and Azure SQL Database.

Section: Administration Level: Medium

Question:

You are reviewing the memory usage of a Windows Server running SQL Server. It appears to have almost run out of memory.

You add additional memory, and monitor the usage of the memory by SQL Server. It appears to always be constantly increasing, until the server is almost out of memory again.

2026-01-10

This is the start of a new series of blog posts dedicated to Microsoft Fabric Real-Time Intelligence or RTI. I think RTI is an important aspect of Microsoft Fabric, yet it is currently underutilized. I hope to try to help change that.

So why, RTI ?

Let’s start with a simple idea. Real time intelligence (or RTI) is about shrinking the delay between when data is created and when you can act on it. In traditional systems, we’re often used to data being collected, stored, and only analyzed later, maybe overnight or even weekly. That’s fine for long term reporting, but it’s too slow for situations where immediate action matters.

2026-01-09

This is a post in the SQL Interview series. These aren’t trick or gotcha questions, they’re just questions designed to scope out a candidate’s knowledge around SQL Server and Azure SQL Database.

Section: Development Level: Intro

Question:

You are reviewing the design of a database and note that in the dbo.Customers table, there is a column called CustomerTimestamp that has the timestamp data type.

Can you extract the date from the CustomerTimestamp column by using the CONVERT function?

2026-01-08

This is a post in the SQL Interview series. These aren’t trick or gotcha questions, they’re just questions designed to scope out a candidate’s knowledge around SQL Server and Azure SQL Database.

Section: Administration Level: Medium

Question:

You are tracing queries using Extended Events. Two queries have exactly the same execution plan, and the same plan costs. In the trace, one query showed a duration of 2 minutes. The other query showed a duration of over an hour.

2026-01-07

This is a post in the SQL Interview series. These aren’t trick or gotcha questions, they’re just questions designed to scope out a candidate’s knowledge around SQL Server and Azure SQL Database.

Section: Administration Level: Intro

Question:

You successfully create a full backup of a database that is in full recovery model.

As part of the backup, is the transaction log shrunk?

Answer:

No — a full database backup does not shrink or truncate the transaction log.

2026-01-06

I can’t tell you how many sessions for developers that I have attended, where the demonstration shows an application connecting to a database as the database owner (dbo) or as a system administrator (like sa). Are we then surprised when developers do this in their own applications?

Please don’t do this.

If you’re running a utility application that’s only used by administrators, and is run within a secure part of the environment, that might be ok. But for normal user applications, it’s just not safe to do so, and it’s really poor practice.

2026-01-05