SGA_MAX_SIZE超过MEMORY_TARGET 导致无法启动

SQL> startup mount
\ORA-00844: Parameter not taking MEMORY_TARGET into account
ORA-00851: SGA_MAX_SIZE 3154116608 cannot be set to more than MEMORY_TARGET 1526726656.
DB再启动数据库的时候报SGA_MAX_SIZE超过MEMORY_TARGET，经查发现设置oracle.install.db.config.starterdb.memoryLimit=3000，然而SGA_MAX_SIZE 设置的值大于这个值，所以导致无法启动！！！！
这个DB居然实先木有生成pfile文件，好吧我来讲讲恢复方法

恢复pfile

SQL> create pfile='/opt/app/init.ora' from spfile;

File created.
赶紧修改pfile的SGA_MAX_SIZE 值
然后再恢复数据库
SQL> startup nomount pfile='/opt/app/init.ora';
ORACLE instance started.

Total System Global Area 1068937216 bytes
Fixed Size 2260088 bytes
Variable Size 310379400 bytes
Database Buffers 750780416 bytes
Redo Buffers 5517312 bytes
SQL> alter database mount;

Database altered.

SQL> create spfile from pfile='/opt/app/init.ora';

File created.

SQL> alter database open;

Database altered.

现在要记得创建pfile
SQL> create pfile from spfile;

File created.