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触发器(七、DDL触发器在OGG维护中的应用)

2018-03-10 14:54 218 查看

场景描述

有一个业务系统,做了OGG备库用于统计查询。

生产库的维护由系统管理员负责,而备库的日常维护由专职DBA负责。

系统厂商在对生产环境进行升级时,经常会修改数据结构。

DBA很快发现了OGG报错,查看日志是数据结构变更,于是向生产库系统管理员要数据变更清单。

生产库管理员再向系统厂商要,有时候系统厂商没有事先准备脚本,升级时在线的部分修改没有记录,导致DBA不停的跟踪错误信息,两边比对数据结构,再到备库中进行修改,烦不胜烦。

之后,DBA在生产库中创建了DDL触发器,用于跟踪数据结构变更,用来解决这个烦恼。

DDL触发器能对数据库中的DDL操作进行触发,包括

实施步骤如下:

1.在生产环境的监控用户CZFX下创建DDL操作记录表

SQL> CREATE TABLE CZFX.T_DDL_OGG
2  (GUID           VARCHAR2(50)   DEFAULT SYS_GUID() PRIMARY KEY
3  ,CREATED        DATE           DEFAULT SYSDATE
4  ,EVENT          VARCHAR2(30)
5  ,LOGIN_USER     VARCHAR2(30)
6  ,OBJ_NAME       VARCHAR2(30)
7  ,OBJ_OWNER      VARCHAR2(30)
8  ,OBJ_TYPE       VARCHAR2(30)
9  ,COLUMN_NAME    VARCHAR2(30)
10  ,DDL_SQL        VARCHAR2(4000)
11  ,ISDEAL         VARCHAR2(1)   DEFAULT '0'
12  ) TABLESPACE CZFX;
Table created
Executed in 0.031 seconds


2.用SYS用户创建DDL触发器

(注意:其他数据库用户也可以创建DDL触发器,但经测试只能捕捉到用户自己的DDL操作)

SQL> CREATE OR REPLACE TRIGGER TRI_DBDDL
2  AFTER CREATE OR DROP OR ALTER ON DATABASE
3  WHEN (ORA_DICT_OBJ_TYPE='TABLE')
4  DECLARE
5    V_GUID   VARCHAR2(50);
6   T_SQL_TXT ORA_NAME_LIST_T:=ORA_NAME_LIST_T();
7    N_COUNT    PLS_INTEGER;
8   V_SQL_TXT  VARCHAR2(4000);
9  BEGIN
10    V_GUID:=SYS_GUID();
11   N_COUNT:=ORA_SQL_TXT(sql_text => T_SQL_TXT);
12   FOR I IN 1..N_COUNT LOOP
13     V_SQL_TXT:=V_SQL_TXT||T_SQL_TXT(I)||CHR(10);
14   END LOOP;
15    INSERT INTO CZFX.T_DDL_OGG(GUID,CREATED,LOGIN_USER,EVENT,OBJ_NAME,OBJ_OWNER,OBJ_TYPE,DDL_SQL)
16     VALUES(V_GUID,SYSDATE,ORA_LOGIN_USER,ORA_SYSEVENT,ORA_DICT_OBJ_NAME,ORA_DICT_OBJ_OWNER,ORA_DICT_OBJ_TYPE
17           ,V_SQL_TXT);
18    FOR REC_COLUMN IN(SELECT COLUMN_NAME FROM ALL_TAB_COLUMNS WHERE OWNER=ORA_DICT_OBJ_OWNER AND TABLE_NAME=ORA_DICT_OBJ_NAME)
19    LOOP
20      IF ORA_IS_ALTER_COLUMN(REC_COLUMN.COLUMN_NAME) THEN
21        UPDATE CZFX.T_DDL_OGG SET COLUMN_NAME=LTRIM(COLUMN_NAME||','||REC_COLUMN.COLUMN_NAME,',')
22          WHERE GUID=V_GUID;
23      END IF;
24    END LOOP;
25  END;
26  /
Trigger created
Executed in 0.031 seconds


这个触发器起到了以下效果:

(1)捕捉并记录了数据库中任何用户对表(table)的create、alter、drop操作;

(2)记录了DDL原始语句,这个非常有用,在备库可以直接粘贴;

(3)记录了是哪个用户(登录用户)操作了哪个用户(对象拥有者)的表

3.测试在不同数据库用户下做不同的DDL操作

查看日志表

SQL> SHOW USER
User is "SYS"

SQL> CREATE TABLE TMP_DDL_SYS(COL1 VARCHAR2(1));
Table created
Executed in 0.063 seconds

SQL> select * from CZFX.T_DDL_OGG;
GUID                                               CREATED     EVENT                          LOGIN_USER                     OBJ_NAME                       OBJ_OWNER                      OBJ_TYPE                       COLUMN_NAME                    DDL_SQL                                                                          ISDEAL
-------------------------------------------------- ----------- ------------------------------ ------------------------------ ------------------------------ ------------------------------ ------------------------------ ------------------------------ -------------------------------------------------------------------------------- ------
670898870AB51B9BE0532582290AF84C                   2018/3/10 1 CREATE                         SYS                            TMP_DDL_SYS                    SYS                            TABLE                                                         CREATE TABLE TMP_DDL_SYS(COL1 VARCHAR2(1))                                       0
Executed in 0.094 seconds

SQL> conn system/sys@czkf;
Connected to Oracle Database 11g Enterprise Edition Release 11.2.0.3.0
Connected as system@czkf

SQL>
SQL> CREATE TABLE TMP_DDL_SYSTEM(COL1 VARCHAR2(1));
Table created
Executed in 0.031 seconds
SQL> select * from CZFX.T_DDL_OGG;
GUID                                               CREATED     EVENT                          LOGIN_USER                     OBJ_NAME                       OBJ_OWNER                      OBJ_TYPE                       COLUMN_NAME                    DDL_SQL                                                                          ISDEAL
-------------------------------------------------- ----------- ------------------------------ ------------------------------ ------------------------------ ------------------------------ ------------------------------ ------------------------------ -------------------------------------------------------------------------------- ------
670898870AB51B9BE0532582290AF84C                   2018/3/10 1 CREATE                         SYS                            TMP_DDL_SYS                    SYS                            TABLE                                                         CREATE TABLE TMP_DDL_SYS(COL1 VARCHAR2(1))                                       0
6708DEB8ECF41C9EE0532582290AF3B6                   2018/3/10 1 CREATE                         SYSTEM                         TMP_DDL_SYSTEM                 SYSTEM                         TABLE                                                         CREATE TABLE TMP_DDL_SYSTEM(COL1 VARCHAR2(1))                                    0
Executed in 0.11 seconds

SQL>
SQL> conn czfx/czfx@czkf;
Connected to Oracle Database 11g Enterprise Edition Release 11.2.0.3.0
Connected as czfx@czkf
SQL> CREATE TABLE TMP_DDL_CZFX(COL1 VARCHAR2(1));
Table created
Executed in 0.016 seconds
SQL> ALTER TABLE TMP_DDL_CZFX MODIFY COL1 NUMBER(2);
Table altered
Executed in 0.016 seconds
SQL> ALTER TABLE TMP_DDL_CZFX ADD COL2 VARCHAR2(20);
Table altered
Executed in 0 seconds
SQL> select * from CZFX.T_DDL_OGG;
GUID                                               CREATED     EVENT                          LOGIN_USER                     OBJ_NAME                       OBJ_OWNER                      OBJ_TYPE                       COLUMN_NAME                    DDL_SQL                                                                          ISDEAL
-------------------------------------------------- ----------- ------------------------------ ------------------------------ ------------------------------ ------------------------------ ------------------------------ ------------------------------ -------------------------------------------------------------------------------- ------
670898870AB51B9BE0532582290AF84C                   2018/3/10 1 CREATE                         SYS                            TMP_DDL_SYS                    SYS                            TABLE                                                         CREATE TABLE TMP_DDL_SYS(COL1 VARCHAR2(1))                                       0
6708DEB8ECF41C9EE0532582290AF3B6                   2018/3/10 1 CREATE                         SYSTEM                         TMP_DDL_SYSTEM                 SYSTEM                         TABLE                                                         CREATE TABLE TMP_DDL_SYSTEM(COL1 VARCHAR2(1))                                    0
6708E1B7A1CD1F6CE0532582290A83AF                   2018/3/10 1 CREATE                         CZFX                           TMP_DDL_CZFX                   CZFX                           TABLE                                                         CREATE TABLE TMP_DDL_CZFX(COL1 VARCHAR2(1))                                      0
6708E1B7A1CE1F6CE0532582290A83AF                   2018/3/10 1 ALTER                          CZFX                           TMP_DDL_CZFX                   CZFX                           TABLE                          COL1                           ALTER TABLE TMP_DDL_CZFX MODIFY COL1 NUMBER(2)                                   0
6708E1B7A1CF1F6CE0532582290A83AF                   2018/3/10 1 ALTER                          CZFX                           TMP_DDL_CZFX                   CZFX                           TABLE                                                         ALTER TABLE TMP_DDL_CZFX ADD COL2 VARCHAR2(20)                                   0
Executed in 0.172 seconds

SQL>
SQL> DROP TABLE TMP_DDL_CZFX PURGE;
Table dropped
Executed in 0.031 seconds
SQL> conn sys/sys@czkf AS SYSDBA;
Connected to Oracle Database 11g Enterprise Edition Release 11.2.0.3.0
Connected as sys@czkf AS SYSDBA
SQL> DROP TABLE SYSTEM.TMP_DDL_SYSTEM PURGE;
Table dropped
Executed in 0.047 seconds
SQL> DROP TABLE TMP_DDL_SYS PURGE;
Table dropped
Executed in 0.032 seconds
SQL> select * from CZFX.T_DDL_OGG ORDER BY CREATED;
GUID                                               CREATED     EVENT                          LOGIN_USER                     OBJ_NAME                       OBJ_OWNER                      OBJ_TYPE                       COLUMN_NAME                    DDL_SQL                                                                          ISDEAL
-------------------------------------------------- ----------- ------------------------------ ------------------------------ ------------------------------ ------------------------------ ------------------------------ ------------------------------ -------------------------------------------------------------------------------- ------
670898870AB51B9BE0532582290AF84C                   2018/3/10 1 CREATE                         SYS                            TMP_DDL_SYS                    SYS                            TABLE                                                         CREATE TABLE TMP_DDL_SYS(COL1 VARCHAR2(1))                                       0
6708DEB8ECF41C9EE0532582290AF3B6                   2018/3/10 1 CREATE                         SYSTEM                         TMP_DDL_SYSTEM                 SYSTEM                         TABLE                                                         CREATE TABLE TMP_DDL_SYSTEM(COL1 VARCHAR2(1))                                    0
6708E1B7A1CD1F6CE0532582290A83AF                   2018/3/10 1 CREATE
b24f
CZFX                           TMP_DDL_CZFX                   CZFX                           TABLE                                                         CREATE TABLE TMP_DDL_CZFX(COL1 VARCHAR2(1))                                      0
6708E1B7A1CE1F6CE0532582290A83AF                   2018/3/10 1 ALTER                          CZFX                           TMP_DDL_CZFX                   CZFX                           TABLE                          COL1                           ALTER TABLE TMP_DDL_CZFX MODIFY COL1 NUMBER(2)                                   0
6708E1B7A1CF1F6CE0532582290A83AF                   2018/3/10 1 ALTER                          CZFX                           TMP_DDL_CZFX                   CZFX                           TABLE                                                         ALTER TABLE TMP_DDL_CZFX ADD COL2 VARCHAR2(20)                                   0
6708E1B7A1D01F6CE0532582290A83AF                   2018/3/10 1 DROP                           CZFX                           TMP_DDL_CZFX                   CZFX                           TABLE                                                         DROP TABLE TMP_DDL_CZFX PURGE                                                    0
6708E56C22271F9BE0532582290AF4DB                   2018/3/10 1 DROP                           SYS                            TMP_DDL_SYSTEM                 SYSTEM                         TABLE                                                         DROP TABLE SYSTEM.TMP_DDL_SYSTEM PURGE                                           0
6708E56C22281F9BE0532582290AF4DB                   2018/3/10 1 DROP                           SYS                            TMP_DDL_SYS                    SYS                            TABLE                                                         DROP TABLE TMP_DDL_SYS PURGE                                                     0
8 rows selected
Executed in 0.234 seconds


接下来就通过各种方式通知DBA就可以了,DBA对新增的DDL操作在备库中进行处理,并把记录删掉或标记为已处理。

这样就完成了一个OGG的DDL操作自动管理机制,本人部署完这套东西后,添加了短信提醒功能,在GoldenGate主库出现异常时能够在不联系主库管理员的情况下迅速恢复OGG运行,收益匪浅。

当然,DDL触发器还可以用于跟踪其他数据库对象的DDL操作,支持的DDL命令有以下这些:

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