I just finished a wonderful week in Stockholm, teaching a class for Cornerstone Education. We had 19 SQL Server enthusiasts, all eager to find out everything they could about SQL Server Internals. One questions came up on Thursday that I wasn’t sure of the answer to. I jokingly told the student who asked it to consider it a homework exercise, but ...

In my most recent commentary for SQL Server Magazine, online here:http://www.sqlmag.com/article/training-and-certification2/sql-server-training-options-140429, I talked about different options for making training content available online. As an addendum to that, I’d like to mention that one of my training partners (Benchmark Learning in ...

Books Online has this to say about page splits: When a new row is added to a full index page, the Database Engine moves approximately half the rows to a new page to make room for the new row.  This reorganization is known as a page split.  A page split makes room for new records, but can take time to perform and is a resource ...

The following table summarizes the results from my last two blog entries, showing the CPU time used when performing 5 million clustered index seeks: In test 1, making the clustered index unique improved performance by around 40%. In test 2, making the same change reduced performance by around 70% (on 64-bit systems – more on that later).  ...

Back when my day-to-day duties included database administration work and enterprise architecture, I became rather obsessed with the idea of operational excellence. I read everything I could on the topic. I made a list of favorites, which became somewhat shabby over time, as I dog-eared important pages and scribbled notes in the margins. ...

Remote Desktop Services Component Architecture Poster Grab your own poster! A visual guide to key Remote Desktop Services technologies in Windows Server 2008R2     Virtually Free Get the latest update rollup package for the Hyper-V role in Windows Server 2008 R2 and be sure to bookmark the Windows Virtualization ...

You probably already know that it’s important to be aware of data types when writing queries, and that implicit conversions between types can lead to poor query performance.  Some people have gone so far as to write scripts to search the plan cache for CONVERT_IMPLICIT elements, and others routinely inspect plans for that type of thing when ...

The diagram below shows two data sets, with differences highlighted: To find changed rows using TSQL, we might write a query like this: The logic is clear: join rows from the two sets together on the primary key column, and return rows where a change has occurred in one or more data columns.  Unfortunately, this query only finds one of ...

2 years ago I wrote about monitoring page splits with Extended Events. Only 2 bloggers explored Extended Events feature at that time, so my post was more of a learning than for any practical matter. Yet one question remained open: according to straightforward calculations, after 3 splits of the first page, next split should have occurred on ...

I profiled Adam Machanic's (blog | twitter) excellent stored procedure, SP_WHOISACTIVE, back in August of 2010 in my monthly SQLMag column, Tool Time.  Adam has been diligent about maintaining the tool and adding new features. Read the details on my SQLMag Tool Time column (here - ...