The Oracle Database 12.1 parameter OPTIMIZER_ADAPTIVE_FEATURES has been made OBSOLETE (i.e. must be removed from the SPFILE when upgrading) in Oracle Database 12.2.
It gets replaced with two parameters of whom one is enabled, the other one is disabled by default:
- OPTIMIZER_ADAPTIVE_PLANS=TRUE by default
- OPTIMIZER_ADAPTIVE_STATISTICS=FALSE by default
Nigel Bayliss, our “Optimizer” Product Manager has blogged about it already with way more detailed insights.
But as Oracle Database 12.2 on-premises is not available how should you deal with this feature in Oracle Database 12.1?