When you submit an SQL statement to , compiles
and then executes the statement. Compilation is a
time-consuming process that involves several steps, including optimization,
the stage in which makes its statement execution plan. A statement
execution plan includes whether to use an index, the join order, and so on.
Unless there are significant changes in the amount of data in a table or
new or deleted indexes, will probably come up with the same statement
execution plan for the same statement if you submit it more than once. This
means that the same statements should share the same plan, and should
not recompile them. allows you to ensure this in the following
ways (in order of importance):