- 이전 버전의 Optimizer features로 고정하기 위한 파라미터
- Oracle upgrade시 실행계획 변화를 확인하는데 유용하게 활용( bad sql 통제/확인 등 )
OPTIMIZER_FEATURES_ENABLE acts as an umbrella parameter for enabling a series of optimizer features based on an Oracle release number.
[활용법]
- SYSTEM =optimizer_features_enable='11.2.0.4'
- SESSION = alter session setoptimizer_features_enable='11.2.0.4';
- SQL =select /*+ optimizer_features_enable('11.2.0.4) */
Database Reference
OPTIMIZER_FEATURES_ENABLE acts as an umbrella parameter for enabling a series of optimizer features based on an Oracle release number.
docs.oracle.com
참고 : www.dba-oracle.com/t_optimizer_features_enable.htm
optimizer_features_enable tips
Question: I just upgraded to Oracle 10g and I'm seeing very bad SQL performance. I had to set optimizer_features_enable=9.0.5, and this fixed by bad performance! What does the optimizer_features_enable parameter do to the SQL optimizer? Can I use optim
www.dba-oracle.com