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 ...

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 ...

For many years, I have been using a C# program to generate the TPC-C compliant data for testing. The program relies on the SqlBulkCopy class to load the data generated as per the TPC-C specifications into the SQL Server tables. In general, the performance of this C# data loader is satisfactory. Lately however, I found myself in a situation ...

A couple of weeks ago I announced a two-day advanced performance seminar in New York City, which will be delivered in July. This seminar will cover SQLCLR and parallelism techniques to help you take performance well beyond the levels that typical tuning exercises yield. Check out the links for more details, including a full outline. Thanks to the ...

I am pleased to announce that I will be delivering two days of training in New York City, July 14 and 15. This seminar focuses on achieving ''next-level'' performance--going beyond that which you can gain via normal tuning methodologies. The vehicles for this performance improvement are two technologies that I've been pushing on this blog and in ...

  I just ran across what I think is a newly published white paper on parallel  processing in SQL Server 2008 R2. The date is October 2010 but this is the first time I have seen it so I am not 100% sure how new it really is. Maybe you have seen it already but if not I recommend taking a look. So far I haven’t had time to read it ...

I am honored to have been selected for a second year in a row to present a full-day seminar at the PASS Summit. This year's seminar will be a ''post-con'', and will be delivered on Friday, November 12. The title of the seminar is ''A Day of Doing Many Things at Once: Multitasking, Parallelism, and Process Distribution,'' and the focus is on ...

Last month a new PASS Virtual Chapter was introduced, one with a theme that is near and dear to much of what I like to work on: performance. Tomorrow, Tuesday August 3rd at noon Eastern time, the chapter will have its second meeting, and I will be doing the presentation. The topic is Parallelism and Performance. Here's the abstract:In ...