视图：dba_hist_wr_control查询到两套库的awr保留策略

问题描述：有一个问题，有同事在查询awr报告收集策略的时候，发现有两个库的策略，一套自己的，另一套已经找不到属于谁了，那么究竟是什么情景会出现这样的场景呢？

1.一开始网上找解答也没有得到解决，询问技术群和同事得到了两种解答，得到了两种比较靠谱的答案。一种是怀疑这个库之前导入过AWR报告;一种是说这个库之前做过不完全恢复，导致遗留了两种不通的DBID

2.测试了导入导出AWR报告的方式，将一个库的AWR报告导入到另一个库中，测试中使用的是11g到19c的环境

导出AWR：@$ORACLE_HOME/rdbms/admin/awrextr.sql

导入AWR：@$ORACLE_HOME/rdbms/admin/awrload.sql

3.11g导出AWR报告：

SQL> @$ORACLE_HOME/rdbms/admin/awrextr.sql
~~~~~~~~~~~~~
AWR EXTRACT
~~~~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~  This script will extract the AWR data for a range of snapshots  ~
~  into a dump file.  The script will prompt users for the       ~
~  following information:                       ~
~     (1) database id                           ~
~     (2) snapshot range to extract                   ~
~     (3) name of directory object                   ~
~     (4) name of dump file                       ~
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Databases in this Workload Repository schema
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

   DB Id     DB Name      Host
------------ ------------ ------------
* 459838110  PROD      orcl

The default database id is the local one: ' 459838110'.  To use this
database id, press <return> to continue, otherwise enter an alternative.

Enter value for dbid: 459838110

Using 459838110 for Database ID

Specify the number of days of snapshots to choose from
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Entering the number of days (n) will result in the most recent
(n) days of snapshots being listed.  Pressing <return> without
specifying a number lists all completed snapshots.

Enter value for num_days: 10

Listing the last 10 days of Completed Snapshots

DB Name        Snap Id      Snap Started
------------ --------- ------------------
PROD           141 03 Jun 2021 15:16
           142 03 Jun 2021 16:00
           143 11 Jun 2021 11:15
           144 11 Jun 2021 12:06

Specify the Begin and End Snapshot Ids
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Enter value for begin_snap: 141
Begin Snapshot Id specified: 141

Enter value for end_snap: 144
End   Snapshot Id specified: 144

Specify the Directory Name
~~~~~~~~~~~~~~~~~~~~~~~~~~

Directory Name               Directory Path
------------------------------ -------------------------------------------------
DATA_FILE_DIR               /u01/app/oracle/product/11.2.0/dbhome_1/demo/sche
                   ma/sales_history/

DATA_PUMP_DIR               /u01/app/oracle/admin/PROD/dpdump/
GGS_DDL_TRACE               /u01/app/oracle/diag/rdbms/prod/PROD/trace
LOG_FILE_DIR               /u01/app/oracle/product/11.2.0/dbhome_1/demo/sche
                   ma/log/

MEDIA_DIR               /u01/app/oracle/product/11.2.0/dbhome_1/demo/sche
                   ma/product_media/

Directory Name               Directory Path
------------------------------ -------------------------------------------------
ORACLE_OCM_CONFIG_DIR           /u01/app/oracle/product/11.2.0/dbhome_1/ccr/hosts
                   /orcl/state

ORACLE_OCM_CONFIG_DIR2           /u01/app/oracle/product/11.2.0/dbhome_1/ccr/state
SS_OE_XMLDIR               /u01/app/oracle/product/11.2.0/dbhome_1/demo/sche
                   ma/order_entry/

SUBDIR                   /u01/app/oracle/product/11.2.0/dbhome_1/demo/sche
                   ma/order_entry//2002/Sep

XMLDIR                   /u01/app/oracle/product/11.2.0/dbhome_1/rdbms/xml

Choose a Directory Name from the above list (case-sensitive).

Enter value for directory_name: DATA_PUMP_DIR

Using the dump directory: DATA_PUMP_DIR

Specify the Name of the Extract Dump File
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The prefix for the default dump file name is awrdat_141_144.
To use this name, press <return> to continue, otherwise enter
an alternative.
这里schema名称必须是oracle数据库中不存在的，不然会异常退出，必须是两个数据库之间没有的schema名字
Enter value for file_name: AWREXPIMP

Using the dump file prefix: AWREXPIMP
|
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|  The AWR extract dump file will be located
|  in the following directory/file:
|   /u01/app/oracle/admin/PROD/dpdump/
|   AWREXPIMP.dmp
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|  *** AWR Extract Started ...
|
|  This operation will take a few moments. The
|  progress of the AWR extract operation can be
|  monitored in the following directory/file:
|   /u01/app/oracle/admin/PROD/dpdump/
|   AWREXPIMP.log
|

Channel(Socket) closed from remote host(ks) at 12:29:37.

查询当前库的DBID

SQL> select dbid from v$database;

      DBID
----------
 459838110

4.导入AWR到19c库，将需要导入的dmp文件提前放到目标库的directories下，导入过程输入的时候注意不要加文件后缀，要不然会遇到各种报错

SQL> @?/rdbms/admin/awrload
~~~~~~~~~~
AWR LOAD
~~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~  This script will load the AWR data from a dump file. The   ~
~  script will prompt users for the following information:    ~
~     (1) name of directory object                  ~
~     (2) name of dump file                      ~
~     (3) staging schema name to load AWR data into          ~
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Specify the Directory Name
~~~~~~~~~~~~~~~~~~~~~~~~~~

Directory Name               Directory Path
------------------------------ -------------------------------------------------
DATA_PUMP_DIR               /u01/app/oracle/admin/test/dpdump/
JAVA$JOX$CUJS$DIRECTORY$       /u01/app/oracle/product/19.2.0/db_1/javavm/admin/
OPATCH_INST_DIR            /u01/app/oracle/product/19.2.0/db_1/OPatch
OPATCH_LOG_DIR               /u01/app/oracle/product/19.2.0/db_1/rdbms/log
OPATCH_SCRIPT_DIR           /u01/app/oracle/product/19.2.0/db_1/QOpatch
ORACLE_BASE               /u01/app/oracle
ORACLE_HOME               /u01/app/oracle/product/19.2.0/db_1
ORACLE_OCM_CONFIG_DIR           /u01/app/oracle/product/19.2.0/db_1/ccr/state
ORACLE_OCM_CONFIG_DIR2           /u01/app/oracle/product/19.2.0/db_1/ccr/state
SDO_DIR_ADMIN               /u01/app/oracle/product/19.2.0/db_1/md/admin
SDO_DIR_WORK
XMLDIR                   /u01/app/oracle/product/19.2.0/db_1/rdbms/xml
XSDDIR                   /u01/app/oracle/product/19.2.0/db_1/rdbms/xml/sch
                   ema

Choose a Directory Name from the list above (case-sensitive).

Enter value for directory_name: DATA_PUMP_DIR

Using the dump directory: DATA_PUMP_DIR

Specify the Name of the Dump File to Load
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Please specify the prefix of the dump file (.dmp) to load:

Enter value for file_name: AWREXPIMP

Loading from the file name: AWREXPIMP.dmp

Staging Schema to Load AWR Snapshot Data
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The next step is to create the staging schema
where the AWR snapshot data will be loaded.
After loading the data into the staging schema,
the data will be transferred into the AWR tables
in the SYS schema.

The default staging schema name is AWR_STAGE.
To use this name, press <return> to continue, otherwise enter
an alternative.

Enter value for schema_name: AWRUSE

Using the staging schema name: AWRUSE

Choose the Default tablespace for the AWRUSE user
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Choose the AWRUSE users's default tablespace.  This is the
tablespace in which the AWR data will be staged.

TABLESPACE_NAME
------------------------------------------------------------
CONTENTS                   DEFAULT TABLESPACE
------------------------------------------ ------------------
SYSAUX
PERMANENT                   *

USERS
PERMANENT

Pressing <return> will result in the recommended default
tablespace (identified by *) being used.

Enter value for default_tablespace: USERS

Using tablespace USERS as the default tablespace for the AWRUSE

Choose the Temporary tablespace for the AWRUSE user
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Choose the AWRUSE user's temporary tablespace.

TABLESPACE_NAME
------------------------------------------------------------
CONTENTS                   DEFAULT TEMP TABLESPACE
------------------------------------------ -----------------------
TEMP
TEMPORARY                   *

Pressing <return> will result in the database's default temporary
tablespace (identified by *) being used.

Enter value for temporary_tablespace: TEMP

Using tablespace TEMP as the temporary tablespace for AWRUSE

... Creating AWRUSE user

|
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|  Loading the AWR data from the following
|  directory/file:
|   /u01/app/oracle/admin/test/dpdump/
|   AWREXPIMP.dmp
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|  *** AWR Load Started ...
|
|  This operation will take a few moments. The
|  progress of the AWR load operation can be
|  monitored in the following directory/file:
|   /u01/app/oracle/admin/test/dpdump/
|   AWREXPIMP.log
|
... Dropping AWRUSE user

End of AWR Load

查询目标库19c的DBID

SQL> select DBID from v$database;

      DBID
----------
2371813226

查询当前的dba_hist_wr_control

SQL> r
  1* select * from dba_hist_wr_control

      DBID SNAP_INTERVAL                                   RETENTION                                   TOPNSQL            CON_ID   SRC_DBID SRC_DBNAME
---------- --------------------------------------------------------------------------- --------------------------------------------------------------------------- -------------------- ---------- ---------- ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
2371813226 +00000 01:00:00.0                                   +00008 00:00:00.0                               DEFAULT             0 2371813226 test
 459838110 +00000 01:00:00.0                                   +00008 00:00:00.0                               DEFAULT             0  459838110

在生成awr报告的时候也可以看到

Instances in this Workload Repository schema
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  DB Id      Inst Num    DB Name      Instance      Host
------------ ---------- ---------    ----------   ------
  459838110     1    PROD         PROD      orcl
* 2371813226     1    TEST         test      rac1

如果想要清理掉这个信息

SQL> exec dbms_swrf_internal.unregister_database(459838110);

PL/SQL procedure successfully completed.

SQL> select * from dba_hist_wr_control;

      DBID SNAP_INTERVAL                                   RETENTION                                   TOPNSQL            CON_ID   SRC_DBID SRC_DBNAME
---------- --------------------------------------------------------------------------- --------------------------------------------------------------------------- -------------------- ---------- ---------- ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
2371813226 +00000 01:00:00.0                                   +00008 00:00:00.0                               DEFAULT             0 2371813226 test

5.再有一种可能是不完全恢复会不会导致出现两种DBID，还没有测试，

incarnation：

Resetlogs命令表示一个数据库逻辑生存期的结束和另一个数据库逻辑生存期的开始，Oracle把这个数据库逻辑生存期称为incarnation；每次使用resetlogs打开数据库，就会使incarnation + 1，也就是产生一个新的incarnation；如果想要恢复到之前incarnation的scn/time，就需要先恢复到之前的incarnation；

RMAN> list incarnation;

using target database control file instead of recovery catalog

List of Database Incarnations
DB Key  Inc Key DB Name  DB ID            STATUS  Reset SCN  Reset Time
------- ------- -------- ---------------- --- ---------- ----------
1       1       TEST     2371813226       PARENT  1          2019:04:1700:55:59
2       2       TEST     2371813226       CURRENT 1920977    2021:05:2716:46:36

参考这个文档在同一套库上恢复的，DBID是不会发生改变的

https://www.cnblogs.com/bicewow/p/11205685.html