The Parallelism Operator appears in an execution plan when SQL Server decides to execute parts of a query in parallel across multiple processors. The goal is to improve query performance by dividing the workload, allowing SQL Server to process data faster for large and complex queries. Parallelism is most beneficial when working with large datasets, complex joins, or aggregation operations.
Icon of Parallelism operator
For example
Suppose we have a bundle of paper
and we want to count it. I can count it myself or I distribute this bundle with
our team’s member and team member can count and aggregate then and get the
total count. This has advantage like we will get the count very quickly. And
Disadvantage of this like we are consuming expensive resource. In same way in
the SQL server for the complex task SQL server distribute the task in multiple
threads to perform the task. This process known as Parallelism in SQL server.