SQL Server Database Engine has two major components: Relational Engine and Storage Engine. We have already covered the SQL Server Storage Engine architecture in the first chapter of this book. In this section, we'll be covering the SQL Server Relational Engine architecture and other topics to optimize the SQL Server Relational Engine.
The SQL Server Relational Engine is also known as the query processor because it produces the optimal execution plan for your query or each query stored in a batch or stored procedure. Then, it executes this query plan to deliver the desired results to the client in a format specified in the submitted Transact-SQL statement.
The following diagram outlines the query optimization process:
The key phases of the query optimization process are explored in the next sections.