All the previously posted results (May 25th and May 29th) on this exercise were obtained with query parallelism disabled (i.e. the sp_configure ‘max degree of parallelism’ option was set to 1).   Since the following test query is sensitive to query parallelism, we need to see what impact query parallelism may have.   DBCC ...

This is another follow-up on the T-SQL exercise.   So the test query below is rather simple:   DBCC DROPCLEANBUFFERS go SELECT COUNT(*) FROM dbo.test;   But beneath its simple appearance, many factors are at play and interact in a complex way to influence the query performance. In other words, trying to predict its ...

Here is a T-SQL scripting exercise in case you have a few minutes to spare or are bored with whatever else you are doing.    Objective The task is to write a simple T-SQL script to generate and load 4,000,000 rows into a test table. The objective is to make the following simple test query to have the worst performance in terms of ...