ORA-00839: SGA_TARGET cannot be modified to the specified value？

Oracle 修改参数，启动报错

SQL> alter system set memory_max_target = 12G scope = spfile;           
SQL> alter system set memory_target = 12G scope = spfile; 

ALTER SYSTEM SET MEMORY_TARGET = 11G;
ALTER SYSTEM SET SGA_TARGET = 0;
ALTER SYSTEM SET PGA_AGGREGATE_TARGET = 0;

配置文件更改成 上面三个语句的参数，启动还是报错。