Scary SQL Server stuff: tombstones, phantoms, ghosts and zombies

This post mixes the spirit of Halloween and the passion for SQL Server 🙂

Have you noticed how SQL Server has a number of things that seem right out of a horror movie?

As a test of your SQL Server expertise and for a fun Halloween trivia game, try to describe the items in the list below in the context of SQL Server.

If you can’t, follow the links to figure them out:

• Tombstones. Marking the burial places of your deceased data. If you don’t keep them, you might end up meeting the undead. http://msdn.microsoft.com/en-us/library/ms186771.aspx
• Phantoms. Seeing things that are not there? These haunted queries can only be avoided with proper isolation. http://msdn.microsoft.com/en-us/library/aa259216.aspx
• Deadlocks. Weird things happens when hairy transactions collide. If one of those wraps around you, you might end up as the victim. http://msdn.microsoft.com/en-us/library/ms178104.aspx
• Blobs. Oh, the nightmares from these huge things sucking the air out of your database. Your only way out may be pushing them down a stream. http://msdn.microsoft.com/en-us/library/3517w44b.aspx
• Kill. Why would a database need such a command? Well, make sure you’re well behaved it might never be needed. http://msdn.microsoft.com/en-us/library/ms173730.aspx
• Crypt properties. Tales from a database that implemented additional security. Just make sure you don’t misplace your keys. http://msdn.microsoft.com/en-us/library/ms189536.aspx
• Hash Match. It’s not a competition to see who’s the fastest slasher. http://msdn.microsoft.com/en-us/library/aa237090.aspx
• Drop user. Users don’t really live forever, after all. http://msdn.microsoft.com/en-us/library/ms189438.aspx
• Ghost rows. An army of ghosts, all perfectly lined up? Not really. http://msdn.microsoft.com/en-us/library/ms188436.aspx
• Zombie rowsets. What’s Halloween without zombies, even if they only show up in small places. http://msdn.microsoft.com/en-us/library/aa258325.aspx
• Execute reader. Sounds like a curse on whoever reads your data. But it’s actually quite useful and fast. http://msdn.microsoft.com/en-us/library/9kcbe65k.aspx
• Shadow Copies. Not as scary as it sounds. It’s much scarier when your data goes bad and you don’t have them. http://msdn.microsoft.com/en-us/library/cc966520.aspx
• Nested Triggers. It could be a code for snipers waiting to hit you from the rooftops. But it’s much harder to explain than that. http://msdn.microsoft.com/en-us/library/ms190739.aspx
• RIP. No, it’s not an epitaph. It’s a way to help you clear your tracks and achieve compliance. http://msdn.microsoft.com/en-us/library/bb326650.aspx

And, of course, there’s a number of Wizards all over the place.

If you know any other good ones, please do share in the post comments.

P.S.: I was also reminded by Kalen Delaney of the classic “Halloween Problem” which can cause pretty scary results, as described at http://en.wikipedia.org/wiki/Halloween_Problem. Not specific to SQL Server, but there was a related issue with SQL Server 7: http://support.microsoft.com/kb/248441.

Happy Halloween!

(Reposted from a 2009 blog post that aged quite well)