May 18, SQL Saturday returns yet again to the Atlanta area. At this point I've become a bit of a regular at Atlanta's events; this will be my third one in a row. The team that puts them together is amazing, and produces top quality, super fun and educational days every time. Plus: Taco Mac. Friday, May 17, the event is running a few ...

Summary: A deep dive into SQL Server parallelism, and a potential performance problem with parallel plans that use TOP. There was an interesting question asked by Mark Storey-Smith on dba.stackexchange.com back in October 2011.  He was looking at the execution plan for a query that counts a million rows from a virtual auxiliary table of ...

Another year, another fantastic Atlanta SQL Saturday. Hats off to the team that created the event for delivering a top notch day for the attendees. Thanks to everyone who attended my ''Query Tuning Mastery: The Art and Science of Manhandling Parallelism'' session. Demos are attached. Enjoy, and I'll see you at the next one!

Thanks to everyone who attended my sessions last Friday and Saturday at SQLbits! It was great to meet many new people, not to mention spending some time exploring one of my favorite cities, London. Attached are the demos for each of the two talks I delivered: Query Tuning Mastery: The Art of and Science of Manhandling ParallelismAs a database ...

This time around, I've got five wish list items for T-SQL / DDL, and then one bonus - a parallelism bug. My thinking on the former is that, since we are either about to start (or are just finishing) locking down the code for SQL Server 2012, this is the first moment where some of these suggestions can be seriously considered without the ''but ...

What happens when NUMA affinity meets query parallelism? It gets no respect! SQL Server allows you to affinitize a TCP port to a specific NUMA node or a group of NUMA nodes. Books Online has an article on How to: Map TCP/IP ports to NUMA Nodes. And this BOL article discusses various NUMA affinity scenarios. Recently, I have been playing with ...

Hide databases from users who shouldn't be able to see them This is a long-standing request from Erland Sommarskog which I've highlighted in previous digests. But the underlying problem keeps coming up in multiple venues, so I thought it would be good to call attention to the item one more time. Some will argue that the contained database feature ...

There are a lot of questions on hyperthreading, but not a lot of answers.  There is no shortage of opinions, but very few are based on significant first hand experience or solid test data. We know that the hyperthreading technology in the older generations of the Intel processors was not well received by the SQL Server community. ...

In commenting on my previous post, Greg Linwood and GrumpyOldDBA raised questions about various implications of parallelism. In this post, I’ll look at the impact of different degrees of parallelism on the query performance. I’ll limit my examination on the same query that uses a Cartesian product temp table, as discussed in the previous two posts ...

Last Saturday, September 17, I was lucky to be able to present two sessions at an excellent SQL Saturday in the Atlanta area. The day drew a large crowd and had a great speaker lineup. All in all, a huge success, and a very well-managed event. Congratulations to the organizers! One of the highlights for me, aside from speaking, was helping out ...