Oracle 11g 11.2.0.3升级失败后的两种回退方法

升级环境：

1、RAC 11.2.0.1 to RAC 11.2.0.2

2、RAC 11.2.0.1 to RAC 11.2.0.3

3、RAC 11.2.0.2 to RAC 11.2.0.3

以上DB软件均是通过out-of-place upgrade方法升级。

如果在升级完成后，发现升级过程有问题，需要回退，我们可以选择两种回退办法：
1. 通过闪回数据库的办法还原到11.2.0.1 /11.2.0.3的数据库
2. 执行catdwgrd.sql 降级数据字典

以下我们介绍通过闪回数据库的办法还原到11.2.0.1 /11.2.0.3的数据库

关于执行catdwgrd.sql 降级数据字典详见：How To Downgrade From Database 11.2 To Previous Release (includes 11.2.0.3-11.2.0.1) [ID883335.1]

一、检查已升级的数据库版本（11.2.0.3）

备注：

我们在升级11.2.0.3的数据字典之前已经做了数据库的闪回点

create restore point upgrade_rollback guarantee flashback database;

SQL> SELECT NAME, SCN, TIME, DATABASE_INCARNATION#, GUARANTEE_FLASHBACK_DATABASE, STORAGE_SIZE  FROM V$RESTORE_POINT WHERE GUARANTEE_FLASHBACK_DATABASE='YES'; 

NAME
--------------------------------------------------------------------------------
       SCN
----------
TIME
---------------------------------------------------------------------------
DATABASE_INCARNATION# GUA STORAGE_SIZE
--------------------- --- ------------
UPGRADE_ROLLBACK
   1227989
31-MAR-12 10.21.06.000000000 AM
                    1 YES     16384000

检查版本信息

SQL> select * from global_name;

GLOBAL_NAME
--------------------------------------------------------------------------------
RACDB

SQL> select * from v$version;

BANNER
--------------------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
PL/SQL Release 11.2.0.3.0 - Production
CORE    11.2.0.3.0      Production
TNS for IBM/AIX RISC System/6000: Version 11.2.0.3.0 - Production
NLSRTL Version 11.2.0.3.0 - Production

SQL> col COMP_ID format a10
SQL> col COMP_NAME format a30
SQL> select comp_id,comp_name,version,status,modified from dba_registry

SQL> /

COMP_ID    COMP_NAME                      VERSION                        STATUS                 MODIFIED
---------- ------------------------------ ------------------------------ ---------------------- -----------------------
APEX       Oracle Application Express     3.2.1.00.12                    INVALID                31-MAR-2012 12:04:14
EM         Oracle Enterprise Manager      11.2.0.3.0                     VALID                  31-MAR-2012 11:36:51
ORDIM      Oracle Multimedia              11.2.0.3.0                     VALID                  31-MAR-2012 12:04:14
XDB        Oracle XML Database            11.2.0.3.0                     VALID                  31-MAR-2012 12:04:13
EXF        Oracle Expression Filter       11.2.0.3.0                     VALID                  31-MAR-2012 12:04:12
RUL        Oracle Rules Manager           11.2.0.3.0                     VALID                  31-MAR-2012 12:04:13
OWM        Oracle Workspace Manager       11.2.0.3.0                     VALID                  31-MAR-2012 12:04:11
CATALOG    Oracle Database Catalog Views  11.2.0.3.0                     VALID                  31-MAR-2012 12:04:11
CATPROC    Oracle Database Packages and T 11.2.0.3.0                     VALID                  31-MAR-2012 12:04:11
           ypes

JAVAVM     JServer JAVA Virtual Machine   11.2.0.3.0                     VALID                  31-MAR-2012 12:04:11
XML        Oracle XDK                     11.2.0.3.0                     VALID                  31-MAR-2012 12:04:11
CATJAVA    Oracle Database Java Packages  11.2.0.3.0                     VALID                  31-MAR-2012 12:04:11
RAC        Oracle Real Application Cluste 11.2.0.3.0                     VALID                  31-MAR-2012 12:04:14
           rs

13 rows selected.