在Oracle關閉的狀態下，如何修改引數檔案spfile
因為一些記憶體大小設定的問題，搞不定，一上火，我直接重啟了整臺伺服器。
登入之後，啟動資料庫，還是出錯：
ORA-00844: Parameter not taking MEMORY_TARGET into account
ORA-00851: SGA_MAX_SIZE 2147483648 cannot be set to more than MEMORY_TARGET 1258291200.
ORA-01078: failure in processing system parameters
可是尼瑪，spfile是二進位制檔案，沒法修改啊，怎麼辦？
還好從網上找了些資料，還是有辦法。你碰到的問題，都會有人碰到的。
解決的辦法就是：
通過pfile啟動Oracle–>在Oracle中通過create pfile='' from spfile=''取出spfile的內容（pfile是可以手動修改的）–>修改新建的pfile–>以新的pfile啟動Oracle–>在Oracle中通過create spfile='' from pfile=''獲得修改後的spfile
具體實戰：
SQL> create pfile = '/opt/oracle/product/12.2.0/dbhome/dbs/initORCL.ora' from spfile = '/opt/oracle/product/12.2.0/dbhome/dbs/spfileORCL.ora';
File created.
SQL> startup mount pfile='/opt/oracle/product/12.2.0/dbhome/dbs/initORCL.ora';
此時，引數可能還有一些問題，但你可以開啟initORCL.ora修改了，搞定之後。
SQL> alter database open;
Database altered.
SQL> create spfile = '/opt/oracle/product/12.2.0/dbhome/dbs/spfileORCL.ora' from pfile = '/opt/oracle/product/12.2.0/dbhome/dbs/initORCL.ora';
File created.
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup;
ORACLE instance started.
Total System Global Area 1258291200 bytes
Fixed Size 8792200 bytes
Variable Size 1023412088 bytes
Database Buffers 201326592 bytes
Redo Buffers 24760320 bytes
Database mounted.
Database opened.