Which index type is recommended for queries that run large aggregation workloads?

The recommended index type for queries that run large aggregation workloads is the columnstore index. This type of index is specifically optimized for analytics and data warehousing scenarios where high performance on large volumes of data is required.

Columnstore indexes store data in a columnar format, which significantly reduces the amount of data that needs to be read into memory when executing aggregation queries. By allowing SQL Server to read only the relevant columns required for the aggregation calculations, columnstore indexes help in efficiently compressing data and improve I/O performance. Additionally, they enable parallel processing of queries, which can further enhance performance when dealing with large datasets.

In scenarios involving aggregations, such as calculating sums, averages, or any other aggregate function over large tables, columnstore indexes can offer substantial improvements in query execution speed due to their ability to optimize storage and processing. This makes them highly effective for analytical workloads compared to other index types, which may not provide the same level of performance enhancement in similar scenarios.