CHECKSUM and BINARY_CHECKSUM might not return unique values for different inputs

CHECKSUM and BINARY_CHECKSUM create checksums for text inputs. Checksum values should be different for different input text. However, in some cases, returned values are not always unique for different inputs. You can find patterns of inputs that return same values. This is similar to modulo operator that returns the same remainder if you find the… Read more

SQL Databases on File Shares – It’s time to reconsider the scenario.

For those who have been around databases for any length of time, the idea of putting a database that you care about from either a reliability or performance perspective on an  (SMB – Server Message Block) file share seems like a crazy idea, but recent developments have made SMB-based file shares a very viable platform… Read more

CHECKSUM and Tempdb

You may recall that starting with SQL Server 2005, you have an option available to enable CHECKSUM on the user databases.  For details, please refer to  In fact, any new database created in SQL2005 has CHECKSUM enabled automatically but it does not happen to databases that are upgraded from previous versions of SQL Server. For… Read more

ok – really the last blog post – Mondays, Mystic, and a Museum

My new blog’s not active until September 1st but I wanted to blog about something cool – and totally unrelated to work. Over the weekend Kimberly and I were in Connecticut for the birthday party pig-roast for Carl Franklin (of DotNetRocks fame) along with our good friends Richard Campbell – also from DotNetRocks – and his… Read more

Splits and unions…

Hey folks, This is my last blog post on the SQL Server Storage Engine blog as I’ve made the decision to leave Microsoft and join Kimberly running her company, This lets me indulge my passion for teaching and consulting full-time and lets me work with my best friend. My last day at Microsoft is August 31st… Read more

Would you like to join the Storage Engine PM team?

We have some job openings on the Storage Engine Program Management team – if you’re looking for a great career opportunity helping to drive the product you love using, check them out. What does a Program Manager do? This blog entry by Steven Sinofsky (one of our Senior VPs) sums it up nicely. Here are… Read more

What’s the difference between database version and database compatibility level?

I had a question this week from someone who’d heard me say at SQL Connections (paraphrasing) “database compatibility level is mostly about query parsing” and was having trouble trying to forcibly attach a 2005 or 7.0 database to a 2000 server. His confusion is between database compatibility level and database version. Here’s a quick explanation of… Read more

SP2 Maintenance Plan bugs fixed

From the tools team here in Redmond: We recently posted updates to address an issue in two SP2 Maintenance Plantasks. The KB article describes the symptoms as follows:FIX: The Check Database Integrity task and the Execute T-SQL Statement taskin a maintenance plan may lose database context in certain circumstances inSQL Server 2005In Microsoft SQL Server… Read more

New whitepaper on Online Indexing Operations

A great new whitepaper has just been published on TechNet – Online Indexing Operation in SQL Server 2005. It gives a detailed explanation of the online index build process plus guidelines and best practices for implementing online indexing in production. Well worth reading. While I’m on the subject, some other whitepapers around the Storage Engine… Read more