Oracle Core: Essential Internals for DBAs and Developers

What Is a Parse Call?

There are two key concepts that need to be kept separate when we speak of parsing—one is the action of parsing, the other is a program subroutine called a parse call. It may come as a surprise, but

• a parse call may not happen in your code when you think it ought to
• a parse call does not necessarily result in any optimization taking place
• a parse call does not necessarily result in any parsing taking place
• parsing and optimization can occur on an execute call, not just on a parse call

If we go back to our simple loop program and check the session statistics for the two variants of the SQL statement we have constructed (see core_dc_activitiy_03.sql in the code library), we will see the following results about parse calls: ...