Optimizer Adaptive Features

Controlling Adaptive Features 12.1

optimizer_adaptive_features=TRUE
optimizer_adaptive_reporting_only=FALSE

Notes
There is a patch available for 12.1 that allows it to work like 12.2

Controlling Adaptive Features 12.2

optimizer_adaptive_plans=TRUE

Notes

Setting this parameter to false disables the following adaptive features:

• Nested loop join/hash join selection
• Star transformation bitmap pruning
• Adaptive parallel distribution method

optimizer_adaptive_statistics=TRUE

Notes
Setting this parameter to false

• Disables SQL plan directives
• disables statistics feedback for joins
• Disables adaptive dynamic sampling for parallel execution
• Preserves the statistics feedback functionality that was introduced in Oracle Database 11g.
• Does not control the creation of SQL plan directives. SQL plan directives will be created even if this parameter is false, but they will not be used to refine SQL execution plans with dynamic sampling.