SQL Execution Plan related definitions

1. Physical operation (physical operation)

The physical operation that will occur on the database engine.

2. Logical operation (logical operation)

Logical operation corresponding to Microsoft's query processing conceptual model.

(for example, for a join operator, its physical Operation property represents the join algorithm used (nested loops, merges, hashes), and the Logical operation property represents the type of logical join used (inner joins, outer joins, semi-joins, and so on). When an operator does not have a corresponding logical operation, the value of the item and the physical operation display the same value. ）

3. Actual number of rows (actual rows)

　　　　　　　　The actual number of rows returned from the operator (shown only in the actual schedule).

4. Estimated I/O cost and estimated CPU cost (estimated I/O overhead and estimated CPU overhead)

The estimated cost of the operator on a specific resource (I/O or CPU). These two measurements can help you determine whether the operator is I/O intensive or CPU-intensive

5. Estimated number of executions and number of executions (estimated executions and executions)

　　　　　　　　The operator estimates the number of executions and the actual number of executions.

6. Estimated operation cost (estimated operator overhead)

The overhead of performing a specific operation.

7. Estimated subtree cost (estimated subtree size)

It represents the cumulative total cost of the entire subtree until the current node.

8. Estimated number of rows (estimated rows)

The number of rows that the operator expects to return. In some cases, by observing the difference between the actual number of rows and the estimated number of rows, you can find out the overhead problems caused by insufficient statistics or other reasons.

9, the bottom of the information window

Shows some additional information about the operator, such as the associated object name, output, parameters, and so on.

SQL Execution Plan related definitions