Sql-Server

Database mirroring was added way in SQL Server 2005. One of the features added to it later in SQL Server 2008 was auto page repair. When SQL Server 2012 was released, Availability Groups also offered auto page repair.

Just how useful is this feature though ?

I’ll start by saying that it can’t hurt.

When SQL Server is reading a page on the primary replica and receives an unrecoverable I/O error (typically but not always, an error 823 for a checksum error), it will try to repair the page when:

2026-07-29

I work with a lot of SQL Server databases that are poorly normalized. One of my pet dislikes is the column to rule them all.

Here are simple tests:

• If I ask you what’s stored in a column and you can’t tell me a single answer, then you’ve got a problem.
• If you need to refer to another column to work out what’s in the first column, then you’ve got a problem.

Here are some examples:

2026-07-27

Intrusions into computer systems are happening all the time now. We need to address this issue as an industry, but it’s important to understand that the way we design databases plays a big role in the impacts that occur during intrusions.

If you don’t accept that you could have an intrusion, you are living in La La Land. (See https://en.wikipedia.org/wiki/Fantasy_prone_personality )

A bug in any one of the frameworks that you use, the code that you write, the protocols that you use, the operating system or hosting services that you use can potentially expose you to an intrusion.

2026-07-25

If I want accounting advice, it’s unlikely that I’d ask my dentist for that advice.

Accountants and IT

Many years ago, I created applications for food wholesalers. When the owners of these businesses decided to get a new or better computing system, invariably they’d speak to their accountants. I understand the reasons why that might seem logical to them at first, but what I saw when these clients did this, is that they invariably ended up with the wrong systems.

2026-07-19

Just after I was born, my mother and father called me Gregory. Ever since then, everyone has called me Greg. And that included my parents. To the day she died, my mother called me Greg and so did my dad while he was alive (miss you both).

I have friends who tell me that the only time their mothers used their full names was when they were in trouble for some reason.

2026-07-17

I’ve pointed out in previous blog posts that I’m not a fan of ORMs. What I’m even less of a fan of is code-first design, particularly in combination with an ORM like the Entity Framework.

It might seem cool and shiny and if you are just whipping up a small proof of concept or test app, please feel free to do it, but the minute you think of doing it for enterprise systems, please just don’t. And if you have colleagues wanting to do this, just say no.

2026-07-15

I work with data. I understand that for most organizations, that the data they own is the most valuable asset the company owns.

One thing I’ve learned from working with data is that unlike application software, data generally outlives generations of applications, is often used by many different applications, and typically just morphs from shape to shape over time. It almost never gets totally refreshed.

This is a good thing.

2026-07-09

Memory is a precious resource on most systems today. SQL Server loves memory, so it’s important to avoid wasting it.

One common cause of wasted memory is what we call plan cache pollution. The plan cache is the region where SQL Server stores compiled query plans (and query plan stubs).

There are some nice new DMVs that give you details of what’s in that cache but nothing still compares to one of the older compatibility views sys.syscacheobjects. You can use it to see what’s in your plan cache:

2026-07-07

I spend most of my life in a variety of customer sites. Most of these nowadays tend to be large financial organizations. When I talk to developers in those organizations, and ask them about how they interact with their DBAs, I can’t tell you how often I hear that they try to avoid ever making schema changes, etc. as it takes too long and the process is painful.

When I talk to the DBAs at the same organizations, and I ask them why they resist making schema changes, I hear this:

2026-07-05

Day by day, we’re getting further away from needing to use 32-bit DLLs. One place where I keep coming across them, is when doing integration work. The problem is that there are many 32-bit drivers for older systems, and no-one is going to ever bother to write 64-bit drivers for them. So, if you have to use those drivers, you need to run the 32-bit versions. And SSIS has options that allow you to run 32-bit drivers.

2026-06-29