Enabling Automatic Memory Management

alter system set memory_max_target=50G scope=spfile;

alter system set memory_target=50G scope=spfile;

alter system set sga_max_size=50G  scope=spfile;

alter system set pga_aggregate_target=0 scope=spfile;

alter system set sga_target=0 scope=spfile;

重启实例。

memory_max_target                    big integer 50G

memory_target                         big integer 50G

pga_aggregate_target                  big integer 0

sga_target                            big integer 0

注意：在oracle 11g中新增的内存自动管理的参数MEMORY_TARGET,它能自动调整SGA和PGA，这个特性需要用到/dev/shm共享文件系统，而且要求/dev/shm必须大于MEMORY_TARGET，如果/dev/shm比MEMORY_TARGET小就会报错。见metalinikID 460506.1

ORA-00845: MEMORY_TARGET not supported