Have you ever heard someone make a statement about a SQL Server concept that you weren’t sure about? It’s important to approach these situations with an open mind and a willingness to learn. Recently, I found myself in a similar situation when I overheard someone say that Columnstore Indexes in SQL Server only use Batch Mode, making them incredibly fast. Intrigued by this statement, I decided to investigate further.

Before jumping to conclusions, I believe in information sharing and avoiding confrontations whenever possible. So, I decided to conduct a quick test to verify the accuracy of the statement. I pulled up my earlier article on Columnstore Indexes and copied the script into SQL Server Management Studio. I created two versions of the script: one with a very large table and another with a reasonably small table. I then executed a query that utilized a Columnstore Index on both versions.

The results of my tests were quite interesting. Contrary to the initial statement, I found that Columnstore Indexes can use both Batch Mode and Row Mode. It’s not a matter of using one exclusively over the other. I shared my findings with the person who made the statement, providing them with a detailed email explaining the results of my tests. To my surprise, they acknowledged their mistake and thanked me for sharing the information instead of engaging in an argument without any evidence.

So, let’s dive into the concept of Columnstore Index modes. Batch mode processing in SQL Server refers to the execution of operations on a batch of rows, typically around 1000 rows. This mode utilizes algorithms optimized for multicore CPUs and increased memory throughput. It spreads metadata access costs and overhead over all the rows in a batch, leading to superior performance. Additionally, batch mode processing operates on compressed data whenever possible, further enhancing performance.

It’s important to note that while Columnstore Indexes can use both Batch Mode and Row Mode, Batch Mode processing is only available for Columnstore Indexes. This means that Columnstore Indexes have the advantage of leveraging the benefits of batch mode processing, resulting in improved query performance.

In conclusion, it’s crucial to verify statements and concepts before accepting them as facts. SQL Server’s Columnstore Indexes can utilize both Batch Mode and Row Mode, with Batch Mode processing offering superior performance due to its optimized algorithms and compressed data operations. By sharing information and conducting tests, we can ensure accurate knowledge and avoid unnecessary confrontations.