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PLSQL_OPTIMIZE_LEVEL

Property Description
Parameter type Integer
Default value 2
Modifiable ALTER SESSION, ALTER SYSTEM
Range of values 0 to 3

PLSQL_OPTIMIZE_LEVEL specifies the optimization level that will be used to compile PL/SQL library units. The higher the setting of this parameter, the more effort the compiler makes to optimize PL/SQL library units.

Values:

  • 0

    Maintains the evaluation order and hence the pattern of side effects, exceptions, and package initializations of Oracle9i and earlier releases. Also removes the new semantic identity of BINARY_INTEGER and PLS_INTEGER and restores the earlier rules for the evaluation of integer expressions. Although code will run somewhat faster than it did in Oracle9i, use of level 0 will forfeit most of the performance gains of PL/SQL in Oracle Database 10g.

  • 1

    Applies a wide range of optimizations to PL/SQL programs including the elimination of unnecessary computations and exceptions, but generally does not move source code out of its original source order.

  • 2

    Applies a wide range of modern optimization techniques beyond those of level 1 including changes which may move source code relatively far from its original location.

  • 3

    Applies a wide range of optimization techniques beyond those of level 2, automatically including techniques not specifically requested.

Generally, setting this parameter to 2 pays off in better execution performance. If, however, the compiler runs slowly on a particular source module or if optimization does not make sense for some reason (for example, during rapid turnaround development), then setting this parameter to 1 will result in almost as good a compilation with less use of compile-time resources.

The value of this parameter is stored persistently with the library unit.