12cR2已经发布一段时间,这里给出一张12c下新出现的可能惹祸特性的列表,可以结合11g的列表一起使用。
我们的宗旨不是要废掉所有新特性,只是把那些还不太成熟的又默认自动生效的积极特性关起来。alter system set "_optimizer_aggr_groupby_elim"=false;
alter system set "_drop_stat_segment"=1;
alter system set "_common_data_view_enabled"=false;
alter system set "_optimizer_dsdir_usage_control"=0; // disable SQL Plan Directive
alter system set optimizer_adaptive_features=false;
alter system set "_optimizer_adaptive_plans"=false;
alter system set "_optimizer_gather_feedback"=false;
alter system set "_optimizer_enable_extended_stats"=false;
alter system set "_optimizer_ads_use_result_cache"=false;
alter system set "_use_single_log_writer"=true scope=spfile; //Multiple log writers feature in Oracle Database 12c can cause instance recovery fails and unexpected
转载自:AskMaclean