Oracle SQL Statement Tuning Page 42 The Execution Phases What Are The Execution Phases? When a user session submits a SQL statement to the database instance, certain instance processes will accept the SQL statement for execution. SQL statement execution involves the following steps: Parse Execute Fetch Parse Phase One of the instance processes will prepare the SQL statement for execution. This is known as the parse and this step is primarily completed by a database component known as the SQL compiler. The following steps are performed within this phase.