問題：我在將Oracle的內存管理方式改為自動內存管理時，出現ORA-00844錯誤，請問應當怎樣解決？

解答：這個錯誤不應該算作Oracle的bug，由于你設置了Oracle的MEMORY_TARGET參數的值小于了SGA_TARGET和PGA_TARGET的總和，因此才會報錯。

[oracle@yangtk ~]$ sqlplus "/ as sysdba"

SQL*Plus: Release 11.1.0.6.0 - PRoduction on Wed Jan 16 07:30:33 2008

Copyright (c) 1982, 2007, Oracle. All rights reserved.

Connected to:
Oracle Database 11g Enterprise Edition Release 11.1.0.6.0 - Production
With the Partitioning, OLAP, Data Mining and Real application Testing options

SQL> set pages 100 lines 120
SQL> show parameter target

NAME TYPE VALUE
------------------------------------ -----------
archive_lag_target integer 0
db_Flashback_retention_target integer 1440
fast_start_io_target integer 0
fast_start_mttr_target integer 0
memory_max_target big integer 0
memory_target big integer 0
pga_aggregate_target big integer 100M
sga_target big integer 252M
SQL> alter system set memory_target = 220m scope = spfile;

System altered.

SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup
ORA-00844: Parameter not taking MEMORY_TARGET into account,
see alert log for more information
 

其實這個錯誤很多情況下是由于人為設置的參數太小造成的。但是Oracle在此處存在兩個問題，首先，沒有通過錯誤信息告訴用戶，是哪些參數的值設置導致的問題。第二點尤為嚴重，Oracle的錯誤信息顯示，進一步的錯誤信息去alert文件中尋找，但是：

SQL> host [oracle@yangtk ~]$ tail -

30 /data/oracle/diag/rdbms/ora11g_p/ora11g/trace/alert_ora11g.log
Wed Jan 16 07:42:00 2008
ARCH shutting down
ARC1: Archival stopped
Wed Jan 16 07:42:00 2008
ARCH shutting down
ARC0: Archival stopped
Wed Jan 16 07:42:00 2008
ARC3: Becoming the 'no FAL' ARCH
ARC3: Becoming the 'no SRL' ARCH
ARC3: Archiving disabled
ARCH shutting down
ARC3: Archival stopped
ARC2: Archival stopped
Thread 1 closed at log sequence 268
Successful close of redo thread 1
Completed: ALTER DATABASE CLOSE NORMAL
ALTER DATABASE DISMOUNT
Completed: ALTER DATABASE DISMOUNT
ARCH: Archival disabled due to shutdown: 1089
Shutting down archive processes
Archiving is disabled
Archive process shutdown avoided: 0 active
Wed Jan 16 07:42:02 2008
Stopping background process VKTM:
ARCH: Archival disabled due to shutdown: 1089
Shutting down archive processes
Archiving is disabled
Archive process shutdown avoided: 0 active
Wed Jan 16 07:42:05 2008
Instance shutdown complete
 

大家可以發現，在alert文件中沒有任何的錯誤信息，看來Oracle在嘗試啟動直接進行了參數的檢查，這個檢查過程就直接報錯了，不過即使報錯也應該記錄到alert文件中，何況錯誤信息中明明顯示要在alert文件中尋找進一步的錯誤。

解決方法：創建pfile，然后修改MEMORY_TARGET的值即可解決此問題。

示例：

SQL> create pfile='/home/oracle/initora11g.ora' from spfile;

File created.

SQL> host echo "memory_target=367001600" >> /home/oracle/initora11g.ora

SQL> startup pfile=/home/oracle/initora11g.ora
ORACLE instance started.

Total System Global Area 267825152 bytes
Fixed Size 1299316 bytes
Variable Size 176163980 bytes
Database Buffers 88080384 bytes
Redo Buffers 2281472 bytes
Database mounted.
Database opened.

SQL> create spfile from pfile='/home/oracle/initora11g.ora';
File created.