Query plan operators of interest
The different icons that are visible in a query execution plan are called operators. Logical operators describe a relational operation – for example, an INNER JOIN operation. Physical operators implement the logical operation with a specific algorithm. So, when we examine a query plan, we are looking at physical operators.
Each physical operator represents a task that needs to be performed to complete the query such as accessing data with a seek or a scan, joining data with a Hash Match join or a Nested Loops join, and sorting data. Some operators are especially relevant to understand while writing T-SQL that scales well. We will look at these operators, understand what they do and how they implement the physical operation behind the logical operation in T-SQL statements, and become familiar with aspects that will be important in the upcoming chapters where we explore T-SQL patterns and anti-patterns.
