_optimizer_adaptive_cursor_sharing=false disables the feature. There are 2 new columns in V$sql , IS_BIND_SENSITIVE and IS_BIND_AWARE that indicate the status for individual cursors. 1.) The parameter "_optimizer_adaptive_cursor_sharing" can be changed "on the fly". This means if you issue an 'alter system set "_optimizer_adaptive_cursor_sharing" = false |true; ' will be reflected in any existing session. Remember, to disable ACS in 11g ,you should also set alter