Guru's Guide to SQL Server Architecture and Internals, The

Logical and Physical Operators

Logical operators describe the relational operations used to process a query. They must be translated into physical operators in order to be executed. Physical operators describe what SQL Server must do to carry out the work (e.g., return the data) requested by the query. Often a logical operator maps to multiple physical operators. Execution plans consist of physical operators because these operators are what tell the LPE component within the server what it needs to do to carry out the work of the query. These physical operators are translated by the LPE component into OLE DB calls from the relational engine to the storage engine to perform the work requested by the query.

Each step in an execution plan corresponds ...