1、验证密码文件已经修改

SQL> create user xff01 identified by xifenfei;
User created.
SQL> grant sysdba to xff01;
Grant succeeded.
SQL> !md5sum $ORACLE_HOME/dbs/orapwora11g
04cedb56b62d94fd7e14124619722348  /opt/oracle/product/11.2.0/db_1/dbs/orapwora11g
SQL> !strings /opt/oracle/product/11.2.0/db_1/dbs/orapwora11g
]\[Z
ORACLE Remote Password file
INTERNAL
A1174901D667F113
18698BFD1A045BCC
XFF01
D32693095588EF4F
SQL> revoke sysdba from xff01;
Revoke succeeded.
SQL> !strings /opt/oracle/product/11.2.0/db_1/dbs/orapwora11g
]\[Z
ORACLE Remote Password file
INTERNAL
A1174901D667F113
18698BFD1A045BCC
XFF01
D32693095588EF4F
SQL> !md5sum $ORACLE_HOME/dbs/orapwora11g
1f6d120acb913a1877cfb0ab57702744  /opt/oracle/product/11.2.0/db_1/dbs/orapwora11g

2、查看基表

SQL> col owner for a20
SQL> col object_name for a30
SQL> SELECT owner,object_name,object_type FROM DBA_objects WHERE object_NAME ='V$PWFILE_USERS';
OWNER                OBJECT_NAME                    OBJECT_TYPE
-------------------- ------------------------------ -------------------
PUBLIC               V$PWFILE_USERS                 SYNONYM
SQL> SELECT table_owner,TABLE_name FROM Dba_Synonyms a WHERE a.synonym_name='V$PWFILE_USERS';
TABLE_OWNER                    TABLE_NAME
------------------------------ ------------------------------
SYS                            V_$PWFILE_USERS
SQL> SELECT owner,object_name,object_type FROM dba_objects WHERE object_name='V_$PWFILE_USERS';
OWNER                OBJECT_NAME                    OBJECT_TYPE
-------------------- ------------------------------ -------------------
SYS                  V_$PWFILE_USERS                VIEW
SQL> set long 1000
SQL> set line 200
SQL> SELECT dbms_metadata.get_ddl('VIEW','V_$PWFILE_USERS','SYS') FROM DUAL;
DBMS_METADATA.GET_DDL('VIEW','V_$PWFILE_USERS','SYS')
--------------------------------------------------------------------------------
  CREATE OR REPLACE FORCE VIEW "SYS"."V_$PWFILE_USERS" ("USERNAME", "SYSDBA", "SYSOPER", "SYSASM") AS
  select "USERNAME","SYSDBA","SYSOPER","SYSASM" from v$pwfile_users
SQL> select * from v$fixed_table where name ='V$PWFILE_USERS';
NAME                            OBJECT_ID TYPE   TABLE_NUM
------------------------------ ---------- ----- ----------
V$PWFILE_USERS                 4294951116 VIEW       65537
SQL> select VIEW_DEFINITION from v$fixed_view_definition where view_name='V$PWFILE_USERS';
VIEW_DEFINITION
--------------------------------------------------------------------------------------------------------
select  USERNAME , SYSDBA , SYSOPER, SYSASM from GV$PWFILE_USERS where inst_id = USERENV('Instance')
SQL> select VIEW_DEFINITION from v$fixed_view_definition where view_name='GV$PWFILE_USERS';
VIEW_DEFINITION
------------------------------------------------------------------------------------------------------------
select inst_id,username,decode(sysdba,1,'TRUE','FALSE'),  decode(sysoper,1,'TRUE','FALSE'),
 decode(sysasm,1,'TRUE','FALSE')  from x$kzsrt where valid=1  and username != 'INTERNAL'
SQL> set line 100
SQL> desc x$kzsrt
 Name                                                  Null?    Type
 ----------------------------------------------------- -------- ------------------------------------
 ADDR                                                           RAW(8)
 INDX                                                           NUMBER
 INST_ID                                                        NUMBER
 USERNAME                                                       VARCHAR2(30)
 SYSDBA                                                         NUMBER
 SYSOPER                                                        NUMBER
 SYSASM                                                         NUMBER
 VALID                                                          NUMBER
SQL> col username for a10
SQL> select * from x$kzsrt;
ADDR                   INDX    INST_ID USERNAME       SYSDBA    SYSOPER     SYSASM      VALID
---------------- ---------- ---------- ---------- ---------- ---------- ---------- ----------
00002B9563678690          0          1 INTERNAL            1          1          0          1
00002B9563678690          1          1 SYS                 1          1          0          1
00002B9563678690          2          1 XFF01               0          0          0          0

从这里可以看出V$PWFILE_USERS视图的基表是x$kzsrt，这里和我们查看的密码文件一样，这些记录都存在，而是在密码文件中有不被strings显示的字符表示了账号是否启用，x$kzsrt.valid用1和0标示
上篇:V$PWFILE_USERS和密码文件关系

分布式事务，简单来说，是指一个事务在本地和远程执行，本地需要等待确认远程的事务结束后，进行下一步本地的操作。如通过dblink update远程数据库的一行记录，如果在执行过程中网络异常，或者其他事件导致本地数据库无法得知远程数据库的执行情况，此时就会发生in doublt的报错。此时需要dba介入，且需要分多种情况进行处理。分布式事务在commit提交时候，会经历3个阶段：
1.PREPARE PHASE
1.1 决定哪个数据库为commit point site。（注，参数文件中commit_point_strength值高的那个数据库为commit point site）
1.2 全局协调者（Global Coordinator）要求所有的点（除commit point site外）做好commit或者rollback的准备。此时，对分布式事务的表加锁。
1.3 所有分布式事务的节点将它的scn告知全局协调者。
1.4 全局协调者取各个点的最大的scn作为分布式事务的scn。（eygle在这篇文章中也测试过）
至此，所有的点都完成了准备工作，我们开始进入COMMIT PHASE阶段，此时除commit point site点外所有点的事务均为in doubt状态，直到COMMIT PHASE阶段结束。
如果数据库在此阶段出现问题，我们查询（假设远程数据库为commit point site，且本地数据库为Global Coordinator）：
本地：

select local_tran_id,state from dba_2pc_pending；
LOCAL_TRAN_ID          STATE
---------------------- ----------------
2.12.64845              collecting

远程：

select local_tran_id,state from dba_2pc_pending；
no rows selected

即表示本地数据库要求其他点做好commit或者rollback准备，现在正在“收集”其他点的数据库的返回信息，但是远程数据库未知状态（in doubt）。我们需要将本地的Global Coordinator的状态清除掉：

execute DBMS_TRANSACTION.PURGE_LOST_DB_ENTRY('local_tran_id');

或者我们在查询的时候发现是如下的状态：
本地：

select local_tran_id,state from dba_2pc_pending；
LOCAL_TRAN_ID          STATE
---------------------- ----------------
2.12.64845             prepared

远程：

select local_tran_id,state from dba_2pc_pending；
no rows selected

即表示本地Global Coordinator已经做好准备，已经将分布式锁放到各个事务的表上，但是远程数据库的状态再次未知（in doubt），我们需要手工的将本地的transaction rollback掉，并且清除分布式事务信息：
本地：

rollback force 'local_tran_id';
execute DBMS_TRANSACTION.PURGE_LOST_DB_ENTRY('local_tran_id');

2.COMMIT PHASE
2.1 Global Coordinator将最大scn传到commit point site，要求其commit。
2.2 commit point尝试commit或者rollback。分布式事务锁释放。
2.3 commit point通知Global Coordinator已经commit。
2.4 Global Coordinator通知分布式事务的所有点进行commit。
如果数据库在此阶段出现问题，我们查询
本地：

select local_tran_id,state from dba_2pc_pending；
LOCAL_TRAN_ID          STATE
---------------------- ----------------
2.12.64845             prepared

远程：

select local_tran_id,state from dba_2pc_pending；
LOCAL_TRAN_ID          STATE
---------------------- ----------------
1.92.66874             commited

即远程数据库可能已经commit，但是本地Global Coordinator未知远程数据库的状态，还是处于prepare的状态。我们需要在如下处理：
本地：

commit force 'local_tran_id';
execute DBMS_TRANSACTION.PURGE_LOST_DB_ENTRY('local_tran_id');

远程：

execute DBMS_TRANSACTION.PURGE_LOST_DB_ENTRY('local_tran_id');

或者我们在查询的时候发现是如下的状态：
本地：

select local_tran_id,state from dba_2pc_pending；
LOCAL_TRAN_ID          STATE
---------------------- ----------------
2.12.64845            commited

远程：

select local_tran_id,state from dba_2pc_pending；
LOCAL_TRAN_ID          STATE
---------------------- ----------------
1.92.66874             commited

即远程数据库和本地数据库均已经完成commit，但是分布式事务的信息尚未清除，我们需要在本地和远程运行：
本地：

execute DBMS_TRANSACTION.PURGE_LOST_DB_ENTRY('local_tran_id');

远程：

execute DBMS_TRANSACTION.PURGE_LOST_DB_ENTRY('local_tran_id');

3.FORGET PHASE
3.1 参与的点通知commit point site他们已经完成commit，commit point site就能忘记（forget）这个事务。
3.2 commit point site在远程数据库上清除分布式事务信息。
3.3 commit point site通知Global Coordinator可以清除本地的分布式事务信息。
3.4 Global Coordinator清除分布式事务信息。
此时如果出现问题，我们查询：
本地：

select local_tran_id,state from dba_2pc_pending；
LOCAL_TRAN_ID          STATE
---------------------- ----------------
2.12.64845            commited

远程：

select local_tran_id,state from dba_2pc_pending；
no rows selected

即远程commit point site已经完成commit，通知Global Coordinator清除本地的分布式事务信息，但是Global Coordinator没有收到该信息。我们需要这样处理：
本地：

execute DBMS_TRANSACTION.PURGE_LOST_DB_ENTRY('local_tran_id');

综上，分布式事务的依次状态为：

phase       local_state    remote_state       action
----------- ---------- ------------------  --------------------------------------------
prepare     collecting       /              本地DBMS_TRANSACTION.PURGE_LOST_DB_ENTRY
            prepared         /              本地rollback force后PURGE_LOST_DB_ENTRY
commit      prepared        commited        本地commit force后本地和远程均PURGE
            commited        commited        本地和远程均PURGE_LOST_DB_ENTRY
forget      commited         /              本地PURGE_LOST_DB_ENTRY

另，当我们遇到使用rollback/commit force的时候，无法正常的清除分布式事务的信息，会报错ORA-02058: no prepared transaction found with ID X.XX.XXXXX时，我们需要通过手工方式来清除该信息。
(注，以下方式修改数据字典，存在风险，使用前请备份好你的数据库)
情况1,在dba_2pc表中还有事务记录，但是实际已经不存在该事务了：

select local_tran_id, state from dba_2pc_pending;
LOCAL_TRAN_ID          STATE
---------------------- ----------------
1.92.66874             prepared

(注:’1.92.66874′的结构为rbs#, slot#, wrap#,此事务在rollback segment #1)
我们再用如下语句找出使用rollback segment #1且状态是active的transaction：

SELECT KTUXEUSN, KTUXESLT, KTUXESQN, /* Transaction ID */
       KTUXESTA Status,
       KTUXECFL Flags
FROM x$ktuxe
WHERE ktuxesta!='INACTIVE'
      AND ktuxeusn= 1; <== 这是rollback segment#，即rbs#
no rows selected

因此我们在rollback force的时候会报错：
ORA-02058: no prepared transaction found with ID 1.92.66874
我们需要如下处理：

set transaction use rollback segment SYSTEM;
delete from sys.pending_trans$
  where local_tran_id = '1.92.66874';
delete from sys.pending_sessions$ where local_tran_id = '1.92.66874';
delete from sys.pending_sub_sessions$ where local_tran_id = '1.92.66874';
commit;

情况2，这种情况比较少见，在dba_2pc表中无法查到分布式事务信息，但是实际上却是存在该分布式事务的：
我们在alertlog中可以看到：
ORA-1591: lock held by in-doubt distributed transaction 1.92.66874
我们查询dba_2pc的表，发现没有分布式事务信息：

select local_tran_id, state from dba_2pc_pending
where local_tran_id='1.92.66874';
no rows selected

但是去查实际的rollback segment信息，却发现有prepared状态的分布式事务存在：

SELECT KTUXEUSN, KTUXESLT, KTUXESQN, /* Transaction ID */
       KTUXESTA Status,
       KTUXECFL Flags
FROM x$ktuxe
WHERE ktuxesta!='INACTIVE'
      AND ktuxeusn= 1;
  KTUXEUSN   KTUXESLT   KTUXESQN STATUS           FLAGS
---------- ---------- ---------- ---------------- ------------------------
         1         92      66874 PREPARED         SCO|COL|REV|DEAD

我们无法做commit force或者rollback force：

rollback force '1.92.66874';
ORA-02058: no prepared transaction found with ID 1.92.66874

我们用如下的方式手工清理：

alter system disable distributed recovery;
insert into pending_trans$ (
    LOCAL_TRAN_ID,
    GLOBAL_TRAN_FMT,
    GLOBAL_ORACLE_ID,
    STATE,
    STATUS,
    SESSION_VECTOR,
    RECO_VECTOR,
    TYPE#,
    FAIL_TIME,
    RECO_TIME)
values( '1.92.66874', /* <== 此处为你的local tran id */
    306206,                  /*                                         */
    'XXXXXXX.12345.1.2.3',   /*  这些值不必更改，   */
    'prepared','P',          /*  是静态参数，可以直接   */
    hextoraw( '00000001' ),  /*  在这个sql中使用                             */
    hextoraw( '00000000' ),  /*                                         */
    0, sysdate, sysdate );
insert into pending_sessions$
values( '1.92.66874',/* <==此处为你的local tran id  */
    1, hextoraw('05004F003A1500000104'),
    'C', 0, 30258592, '',
    146
  );
commit;
commit force '1.92.66874';

此时如果commit force还是出现报错，需要继续执行：

delete from pending_trans$ where local_tran_id='1.92.66874';
delete from pending_sessions$ where local_tran_id='1.92.66874';
commit;
alter system enable distributed recovery;

此时如果没有报错，则执行以下语句：

alter system enable distributed recovery;
and purge the dummy entry from the dictionary, using
connect / as sysdba
alter session set "_smu_debug_mode" = 4;
--注：如果使用auto的undo管理方式，需要执行此步骤，此步骤能避免在后续执行
--purge_lost_db_entry出现ORA-01453 的报错，详细信息可见Bug 2191458
commit;
exec dbms_transaction.purge_lost_db_entry('1.92.66874');

原文:http://www.dbifan.com/200812/how-to-deal-with-distributed-transaction.html

一、V$PWFILE_USERS定义

V$PWFILE_USERS lists all users in the password file, and indicates whether the user has been granted the SYSDBA, SYSOPER, and SYSASM privileges.
Column	    Datatype	Description
USERNAM    VARCHAR2(30)	Name of the user that is contained in the password file
SYSDBA	   VARCHAR2(5)	Indicates whether the user can connect with SYSDBA privileges (TRUE) or not (FALSE)
SYSOPER	   VARCHAR2(5)	Indicates whether the user can connect with SYSOPER privileges (TRUE) or not (FALSE)
SYSASM	   VARCHAR2(5)	Indicates whether the user can connect with SYSASM privileges (TRUE) or not (FALSE)

二、v$pwfile_users与密码文件关系

[oracle@node1 ~]$ sqlplus / as sysdba
SQL*Plus: Release 11.2.0.3.0 Production on Sun Dec 4 19:08:06 2011
Copyright (c) 1982, 2011, Oracle.  All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Partitioning, Oracle Label Security, OLAP, Data Mining,
Oracle Database Vault and Real Application Testing options
--查看密码文件用户权限
SQL> select * from v$pwfile_users;
USERNAME                       SYSDB SYSOP SYSAS
------------------------------ ----- ----- -----
SYS                            TRUE  TRUE  FALSE
SQL> show parameter instance_name;
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------
instance_name                        string      ora11g
--查看系统级别查看密码文件内容
SQL> !strings $ORACLE_HOME/dbs/orapwora11g
]\[Z
ORACLE Remote Password file
INTERNAL
A1174901D667F113
18698BFD1A045BCC
--创建新sysdba用户，查看视图和密码文件变化
SQL> create user xff01 identified by xifenfei;
User created.
SQL> grant sysdba to xff01;
Grant succeeded.
SQL>  select * from v$pwfile_users;
USERNAME                       SYSDB SYSOP SYSAS
------------------------------ ----- ----- -----
SYS                            TRUE  TRUE  FALSE
XFF01                          TRUE  FALSE FALSE
SQL>  !strings $ORACLE_HOME/dbs/orapwora11g
]\[Z
ORACLE Remote Password file
INTERNAL
A1174901D667F113
18698BFD1A045BCC
XFF01
D32693095588EF4F
--删除密码文件
SQL> ! mv $ORACLE_HOME/dbs/orapwora11g $ORACLE_HOME/dbs/orapwora11g_bak
SQL> !ls $ORACLE_HOME/dbs/orapwora11g
ls: /opt/oracle/product/11.2.0/db_1/dbs/orapwora11g: 没有那个文件或目录
--查看视图
SQL>  select * from v$pwfile_users;
no rows selected
SQL>  ! mv $ORACLE_HOME/dbs/orapwora11g_bak $ORACLE_HOME/dbs/orapwora11g
SQL> !ls $ORACLE_HOME/dbs/orapwora11g
/opt/oracle/product/11.2.0/db_1/dbs/orapwora11g
SQL> select * from v$pwfile_users;
USERNAME                       SYSDB SYSOP SYSAS
------------------------------ ----- ----- -----
SYS                            TRUE  TRUE  FALSE
XFF01                          TRUE  FALSE FALSE
--改变sysdba用户权限，视图内容变化
SQL> grant sysoper to xff01;
Grant succeeded.
SQL>  select * from v$pwfile_users;
USERNAME                       SYSDB SYSOP SYSAS
------------------------------ ----- ----- -----
SYS                            TRUE  TRUE  FALSE
XFF01                          TRUE  TRUE  FALSE
--密码文件内容无变化
SQL> !strings $ORACLE_HOME/dbs/orapwora11g
]\[Z
ORACLE Remote Password file
INTERNAL
A1174901D667F113
18698BFD1A045BCC
XFF01
D32693095588EF4F
SQL> revoke sysdba from xff01;
Revoke succeeded.
SQL> select * from v$pwfile_users;
USERNAME                       SYSDB SYSOP SYSAS
------------------------------ ----- ----- -----
SYS                            TRUE  TRUE  FALSE
XFF01                          FALSE TRUE  FALSE
SQL> revoke sysoper  from xff01;
Revoke succeeded.
SQL> select * from v$pwfile_users;
USERNAME                       SYSDB SYSOP SYSAS
------------------------------ ----- ----- -----
SYS                            TRUE  TRUE  FALSE
XFF01                          FALSE FALSE FALSE
SQL> revoke sysoper  from xff01;
Revoke succeeded.
--回收sysdba，sysoper权限后，视图记录消失
SQL> select * from v$pwfile_users;
USERNAME                       SYSDB SYSOP SYSAS
------------------------------ ----- ----- -----
SYS                            TRUE  TRUE  FALSE
--密码文件内容无变化
SQL>  !strings $ORACLE_HOME/dbs/orapwora11g
]\[Z
ORACLE Remote Password file
INTERNAL
A1174901D667F113
18698BFD1A045BCC
XFF01
D32693095588EF4F
--删除其中sysdba用户
SQL> drop user xff01;
User dropped.
--密码文件内容还是无变化
SQL>  !strings $ORACLE_HOME/dbs/orapwora11g
]\[Z
ORACLE Remote Password file
INTERNAL
A1174901D667F113
18698BFD1A045BCC
XFF01
D32693095588EF4F
--重启数据库密码文件依然无变化
SQL> shutdown immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> !strings $ORACLE_HOME/dbs/orapwora11g
]\[Z
ORACLE Remote Password file
INTERNAL
A1174901D667F113
18698BFD1A045BCC
XFF01
D32693095588EF4F

1、如果密码文件不存在或者名称错误，查询v$pwfile_users将得到空记录
2、添加sysdba等权限用户，会记录到密码文件和v$pwfile_users中
3、到回收sysdba等权限用户，密码文件记录依然存在，但是v$pwfile_users中无对应记录

三、远程登录测试

--密码文件记录存在，视图不记录不存在，登录失败
[oracle@node1 ~]$ sqlplus xff01/xifenfei@ora11g as sysdba
SQL*Plus: Release 10.2.0.5.0 - Production on Sun Dec 4 19:42:26 2011
Copyright (c) 1982, 2010, Oracle.  All Rights Reserved.
ERROR:
ORA-01031: insufficient privileges
Enter user-name
--密码文件视图记录均存在，登录成功
[oracle@node1 ~]$ sqlplus sys/xifenfei@ora11g as sysdba
SQL*Plus: Release 10.2.0.5.0 - Production on Sun Dec 4 19:42:10 2011
Copyright (c) 1982, 2010, Oracle.  All Rights Reserved.
Connected to an idle instance.

是否能远程登录，依照v$pwfile_users为准

四、创建密码文件

win：
orapwd file=%ORACLE_HOME%\database\PWD%ORACLE_SID%.ora entries=3 password=manager force=y
linux:
orapwd file=$ORACLE_HOME/dbs/orapw$ORACLE_SID entries=3 password=manager force=y

下篇:V$PWFILE_USERS和密码文件关系(续)