2010-06-18Execution Plans

The optimizer creates the execution plan prior statement execution. The database follows the execution plan in a step-by-step manner. The Optimizer translates the SQL statement to an executable program, in form of an execution plan, very much like a compiler translates source code into an executable.

The execution plan is the first place to look at if the execution takes too long. The following section explains how to retrieve and read an execution plan in various databases.