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 ...

It’s well known that bookmark lookup (aka key lookup in case of a clustered index) is not cheap, especially when it comes to retrieving a lot of data. So I’m not going to rehash the pros and cons of bookmark lookup or why bookmark lookup is expensive. But I’ve noticed that when it comes to discussing bookmark lookup, all the literature seems ...