PLSQL_CODE_TYPE、PLSQL_OPTIMIZE_LEVEL

今天 看题库里发现有提到两个参数PLSQL_CODE_TYPE、PLSQL_OPTIMIZE_LEVEL
PLSQL_CODE_TYPE 有两个值{ INTERPRETED | NATIVE }前者为默认，我觉的应该就是开发语言里编译后的C与汇编语言的区别，一种是字节编码一种是机器码
■ INTERPRETED
PL/SQL library units will be compiled to PL/SQL bytecode format. Such modules are executed by the PL/SQL interpreter engine.
■ NATIVE
PL/SQL library units (with the possible exception of top-level anonymous
PL/SQL blocks) will be compiled to native (machine) code. Such modules will be executed natively without incurring any interpreter overhead.
When the value of this parameter is changed, it has no effect on PL/SQL library units that have already been compiled. The value of this parameter is stored persistently with each library unit.If a PL/SQL library unit is compiled native, all subsequent automatic recompilations of that library unit will use native compilation.
PLSQL_OPTIMIZE_LEVEL
在10g中是0－2，在11G中好像加了个3，10G默认为2，我个人觉的觉的应该就是像vb ,到.net与java一样，级别越高就会提高运行时性能并减低编译时性能
这里有tom大叔举的例子
http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:588234700346069527