通过脚本获得创建用户语句

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标题:通过脚本获得创建用户语句

作者:惜分飞©版权所有[未经本人同意,不得以任何形式转载,否则有进一步追究法律责任的权利.]

在某些情况下,我们需要获得数据库用户的创建脚本(包含系统权限,对象权限,配额等相关语句),这些东西如果人工去做绝对是体力活,在asktom网站上看到相关脚本,做了测试和验证,确实很好

---------------------------------------------
-- ###########################################
---------------------------------------------
create or replace procedure GET_CREATE_USER_DDL
 as
cursor get_username is
select username
from dba_users
--where username IN('CHF','XIFENFEI')
;
begin
for l_user in get_username loop
DBMS_OUTPUT.PUT_LINE('-----------------------');
DBMS_OUTPUT.PUT_LINE('select (case');
DBMS_OUTPUT.PUT_LINE('        when ((select count(*)');
DBMS_OUTPUT.PUT_LINE('               from   dba_users');
DBMS_OUTPUT.PUT_LINE('               where  username = '''||l_user.username||''') > 0)');
DBMS_OUTPUT.PUT_LINE('        then  dbms_metadata.get_ddl (''USER'', '''||l_user.username||''')');
DBMS_OUTPUT.PUT_LINE('        else  to_clob (''   -- Note: User not found!'')');
DBMS_OUTPUT.PUT_LINE('        end ) "--Extracted_DDL" from dual');
DBMS_OUTPUT.PUT_LINE('UNION ALL');
DBMS_OUTPUT.PUT_LINE('-----------------------');
DBMS_OUTPUT.PUT_LINE('select (case');
DBMS_OUTPUT.PUT_LINE('        when ((select count(*)');
DBMS_OUTPUT.PUT_LINE('               from   dba_ts_quotas');
DBMS_OUTPUT.PUT_LINE('               where  username = '''||l_user.username||''') > 0)');
DBMS_OUTPUT.PUT_LINE('        then  dbms_metadata.get_granted_ddl (''TABLESPACE_QUOTA'',
'''||l_user.username||''')');
DBMS_OUTPUT.PUT_LINE('        else  to_clob (''   -- Note: No TS Quotas found!'')');
DBMS_OUTPUT.PUT_LINE('        end )  from dual');
DBMS_OUTPUT.PUT_LINE('UNION ALL');
DBMS_OUTPUT.PUT_LINE('-----------------------');
DBMS_OUTPUT.PUT_LINE('select (case');
DBMS_OUTPUT.PUT_LINE('        when ((select count(*)');
DBMS_OUTPUT.PUT_LINE('               from   dba_role_privs');
DBMS_OUTPUT.PUT_LINE('               where  grantee = '''||l_user.username||''') > 0)');
DBMS_OUTPUT.PUT_LINE('        then  dbms_metadata.get_granted_ddl (''ROLE_GRANT'',
'''||l_user.username||''')');
DBMS_OUTPUT.PUT_LINE('        else  to_clob (''   -- Note: No granted roles found!'')');
DBMS_OUTPUT.PUT_LINE('        end ) from dual');
DBMS_OUTPUT.PUT_LINE('UNION ALL');
DBMS_OUTPUT.PUT_LINE('-----------------------');
DBMS_OUTPUT.PUT_LINE('select (case');
DBMS_OUTPUT.PUT_LINE('        when ((select count(*)');
DBMS_OUTPUT.PUT_LINE('               from   dba_sys_privs');
DBMS_OUTPUT.PUT_LINE('               where  grantee = '''||l_user.username||''') > 0)');
DBMS_OUTPUT.PUT_LINE('        then  dbms_metadata.get_granted_ddl (''SYSTEM_GRANT'',
'''||l_user.username||''')');
DBMS_OUTPUT.PUT_LINE('        else  to_clob (''   -- Note: No System Privileges found!'')');
DBMS_OUTPUT.PUT_LINE('        end ) from dual');
DBMS_OUTPUT.PUT_LINE('UNION ALL');
DBMS_OUTPUT.PUT_LINE('-----------------------');
DBMS_OUTPUT.PUT_LINE('select (case');
DBMS_OUTPUT.PUT_LINE('        when ((select count(*)');
DBMS_OUTPUT.PUT_LINE('               from   dba_tab_privs');
DBMS_OUTPUT.PUT_LINE('               where  grantee = '''||l_user.username||''') > 0)');
DBMS_OUTPUT.PUT_LINE('        then  dbms_metadata.get_granted_ddl (''OBJECT_GRANT'',
'''||l_user.username||''')');
DBMS_OUTPUT.PUT_LINE('        else  to_clob (''   -- Note: No Object Privileges found!'')');
DBMS_OUTPUT.PUT_LINE('        end ) from dual');
DBMS_OUTPUT.PUT_LINE('/');
DBMS_OUTPUT.PUT_LINE('----------------------------------------------------------------------');
end loop;
end;
/
---------------------------------------------
--###########################################
---------------------------------------------
The above proc when called with the foll. will give the SQLs for all users:
---------------------------------------------
-- ###########################################
---------------------------------------------
set pages 50000
set serveroutput on size unlimited
spool /tmp/exec_GET_CREATE_USER_DDL.sql
exec GET_CREATE_USER_DDL
spool off
---------------------------------------------
-- ###########################################
---------------------------------------------
These SQLs generated can in turn be run as follows to get the master-list of all the grants in the database:
---------------------------------------------
-- ###########################################
---------------------------------------------
spool /tmp/GET_CREATE_USER_DDL.sql
conn / as sysdba
set long 1000000000
set pages 50000
exec DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM,'SQLTERMINATOR',TRUE);
@/tmp/exec_GET_CREATE_USER_DDL.sql
spool off
---------------------------------------------
-- ###########################################
---------------------------------------------

通过这个脚本,我们可以在游标地方限制我们需要获得脚本的用户,而最终得到的/tmp/GET_CREATE_USER_DDL.sql就是我们需要的创建用户的对应脚本.

如果只需要获得一个用户创建相关脚本,只需要执行如下sql即可

exec DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM,'SQLTERMINATOR',TRUE);
select (case
        when ((select count(*)
               from   dba_users
               where  username = '&&Username') > 0)
        then  dbms_metadata.get_ddl ('USER', '&&Username')
        else  to_clob ('   -- Note: User not found!')
        end ) Extracted_DDL from dual
UNION ALL
select (case
        when ((select count(*)
               from   dba_ts_quotas
               where  username = '&&Username') > 0)
        then  dbms_metadata.get_granted_ddl( 'TABLESPACE_QUOTA', '&&Username')
        else  to_clob ('   -- Note: No TS Quotas found!')
        end ) from dual
UNION ALL
select (case
        when ((select count(*)
               from   dba_role_privs
               where  grantee = '&&Username') > 0)
        then  dbms_metadata.get_granted_ddl ('ROLE_GRANT', '&&Username')
        else  to_clob ('   -- Note: No granted Roles found!')
        end ) from dual
UNION ALL
select (case
        when ((select count(*)
               from   dba_sys_privs
               where  grantee = '&&Username') > 0)
        then  dbms_metadata.get_granted_ddl ('SYSTEM_GRANT', '&&Username')
        else  to_clob ('   -- Note: No System Privileges found!')
        end ) from dual
UNION ALL
select (case
        when ((select count(*)
               from   dba_tab_privs
               where  grantee = '&&Username') > 0)
        then  dbms_metadata.get_granted_ddl ('OBJECT_GRANT', '&&Username')
        else  to_clob ('   -- Note: No Object Privileges found!')
        end ) from dual
/

批量kill session实现脚本

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标题:批量kill session实现脚本

作者:惜分飞©版权所有[未经本人同意,不得以任何形式转载,否则有进一步追究法律责任的权利.]

在很多使用,因为各种原因,我们需要定时批量的kill一部分session,用来释放数据库部分资源,这里是因为bug导致temp不能正常释放,也可能是因为bug导致pga不释放,还有可能是因为太多inactive占用资源等等.我这里提供了两种方法来实现该功能
存储过程实现kill session

--创建记录表
CREATE TABLE kill_session_record
(
   kill_time        DATE,
   kill_statement   VARCHAR2 (1000)
)
/
--创建kill session存储过程
CREATE OR REPLACE PROCEDURE kill_inactive_session
IS
   CURSOR c
   IS
      SELECT sid, serial#
        FROM v$session s
       WHERE s.status = 'INACTIVE' AND s.username = 'XIFENFEI';
   k_sid      NUMBER;
   k_serial   NUMBER;
BEGIN
   OPEN c;
   FETCH c
   INTO k_sid, k_serial;
   WHILE c%FOUND
   LOOP
      BEGIN
         EXECUTE IMMEDIATE
               'ALTER SYSTEM DISCONNECT SESSION '''
            || k_sid
            || ','
            || k_serial
            || ''' IMMEDIATE';
         INSERT INTO kill_session_record (kill_time, kill_statement)
              VALUES (
                        SYSDATE,
                           'ALTER SYSTEM DISCONNECT SESSION '''
                        || k_sid
                        || ','
                        || k_serial
                        || ''' IMMEDIATE');
      EXCEPTION
         WHEN OTHERS
         THEN
            INSERT INTO kill_session_record (kill_time, kill_statement)
                 VALUES (
                           SYSDATE,
                              'Failure:ALTER SYSTEM DISCONNECT SESSION '''
                           || k_sid
                           || ','
                           || k_serial
                           || ''' IMMEDIATE');
            COMMIT;
      END;
      FETCH c
      INTO k_sid, k_serial;
   END LOOP;
   COMMIT;
   CLOSE c;
END;
/
--设置job定时运行
DECLARE
   job   NUMBER;
BEGIN
   sys.DBMS_JOB.submit (job,
                        what        => 'kill_inactive_session;',
                        next_date   => SYSDATE,
                        interval    => 'TRUNC(SYSDATE + 1) +7/24');
   COMMIT;
   DBMS_OUTPUT.put_line (job);
END;
/

如果是10GR2之前版本,需要把ALTER SYSTEM DISCONNECT SESSION 换成ALTER SYSTEM KILL SESSION

shell kill session

--shell脚本
# more kill_inactive_session.sh
#!/bin/sh
tmpfile0=/tmp/.kill_inactive_0
tmpfile1=/tmp/.kill_inactive_1
tmpfile2=/tmp/.kill_inactive_2
sqlplus / as sysdba <<EOF
spool $tmpfile1
select 'kill time:'||to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') execute_time from dual;
select p.spid,s.sid,s.serial# from v\$process p,v\$session s
where s.paddr=p.addr
and username='XIFENFEI'
and s.status='INACTIVE';
spool off
EOF
cat $tmpfile1>>$tmpfile0
grep "^[0123456789]" $tmpfile1 |awk '{print $1}'>$tmpfile2
for x in `cat $tmpfile2`
do
kill -9 $x
done
rm $tmpfile1 $tmpfile2
--contab 调度
00 07 * * * /u01/script/kill_inactive_session.sh

两个脚本都可以在where中加一些限制条件,来实现你需要kill的会话.数据库级别kill相对系统级别来说更加温和点,建议优先考虑数据库级别kill session.如果要求立即释放资源,可能需要考虑系统级别.两中kill方式对于未提交且是inactive session都会被kill掉,然后回滚事务.

使用IDLE_TIME注意事项

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标题:使用IDLE_TIME注意事项

作者:惜分飞©版权所有[未经本人同意,不得以任何形式转载,否则有进一步追究法律责任的权利.]

需要定时kill非inactive session,一种做法是通过编写脚本or脚本定时运行,从而实现该功能;另外一种方法是通过设置profile中的idle_time来实现该功能,但是这其中有两个细节问题需要注意:1.v$session.status=SNIPED最好做清理,2.未提交事务超时可能强制回滚
使用ORACLE PROFILE准备

SQL> CREATE PROFILE KILLIDLE LIMIT IDLE_TIME 1;
Profile created.
SQL> select * from dba_profiles where profile='KILLIDLE';
PROFILE                        RESOURCE_NAME                    RESOURCE LIMIT
------------------------------ -------------------------------- -------- ------------
KILLIDLE                       COMPOSITE_LIMIT                  KERNEL   DEFAULT
KILLIDLE                       SESSIONS_PER_USER                KERNEL   DEFAULT
KILLIDLE                       CPU_PER_SESSION                  KERNEL   DEFAULT
KILLIDLE                       CPU_PER_CALL                     KERNEL   DEFAULT
KILLIDLE                       LOGICAL_READS_PER_SESSION        KERNEL   DEFAULT
KILLIDLE                       LOGICAL_READS_PER_CALL           KERNEL   DEFAULT
KILLIDLE                       IDLE_TIME                        KERNEL   1
KILLIDLE                       CONNECT_TIME                     KERNEL   DEFAULT
KILLIDLE                       PRIVATE_SGA                      KERNEL   DEFAULT
KILLIDLE                       FAILED_LOGIN_ATTEMPTS            PASSWORD DEFAULT
KILLIDLE                       PASSWORD_LIFE_TIME               PASSWORD DEFAULT
KILLIDLE                       PASSWORD_REUSE_TIME              PASSWORD DEFAULT
KILLIDLE                       PASSWORD_REUSE_MAX               PASSWORD DEFAULT
KILLIDLE                       PASSWORD_VERIFY_FUNCTION         PASSWORD DEFAULT
KILLIDLE                       PASSWORD_LOCK_TIME               PASSWORD DEFAULT
KILLIDLE                       PASSWORD_GRACE_TIME              PASSWORD DEFAULT
16 rows selected.
SQL> ALTER USER CHF PROFILE KILLIDLE;
User altered.
SQL> SELECT USERNAME,PROFILE FROM DBA_USERS where username='CHF';
USERNAME                       PROFILE
------------------------------ ------------------------------
CHF                            KILLIDLE
SQL> SHOW PARAMETER resource_limit
NAME                                 TYPE        VALUE
------------------------------------ ----------- ---------------
resource_limit                       boolean     FALSE
SQL> ALTER SYSTEM SET resource_limit=TRUE;
System altered.

如果要profile生效,需要修改resource_limit=true,IDLE_TIME单位为分钟

测试IDLE_TIME

--session 1
SQL> show user;
USER is "CHF"
SQL> select * from t_xifenfei;
        ID
----------
         1
--删除一条记录
SQL> delete from t_xifenfei;
1 row deleted.
--查询sid
SQL> select sid from v$mystat where rownum=1;
       SID
----------
        20
--开始不操作该会话时间
SQL> select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from dual;
TO_CHAR(SYSDATE,'YY
-------------------
2013-02-12 22:30:02
--session 2
SQL> show user;
USER is "SYS"
--查询时间
SQL> select status,to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from v$session where sid=20;
STATUS   TO_CHAR(SYSDATE,'YY
-------- -------------------
INACTIVE 2013-02-12 22:31:00
--session 1
SQL> select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from dual;
select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from dual
*
ERROR at line 1:
ORA-02396: exceeded maximum idle time, please connect again
----已经报会话超时
--session 2
SQL> select status,to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from v$session where sid=20;
STATUS   TO_CHAR(SYSDATE,'YY
-------- -------------------
SNIPED   2013-02-12 22:34:40
----会话状态为sniped
--session 1
SQL> conn chf/xifenfei
Connected.
SQL> select * from t_xifenfei;
        ID
----------
         1
----事务回滚

SNIPED – An inactive session that has exceeded some configured limits (for example, resource limits specified for the resource manager consumer group or idle_time specified in the user’s profile). Such sessions will not be allowed to become active again.
因为SNIPED的session只有当该session的终端发一个连接信息给数据库,然后终端才会终止连接,如果该客户端一直不发送类似访问,则该连接一直存在,数据库就很可能因为会话数目超过了数据库参数配置从而出现了ORA-00018错误,业务不能正常运行.出现该问题可以通过如下脚本kill -9 pid解决

kill SNIPED session 脚本

#!/bin/sh
tmpfile=/tmp/.kill_sniped
sqlplus system/manager <<EOF
spool $tmpfile
select p.spid from v\$process p,v\$session s
where s.paddr=p.addr
and s.status='SNIPED';
spool off
EOF
for x in `cat $tmpfile | grep "^[0123456789]"`
do
kill -9 $x
done
rm $tmpfile

另外补充说明,IDLE_TIME是对于空闲时间超过了它的配置时间就会去强制终止会话,如果该会话中存在事务,但是inactive时间超过了IDLE_TIME配置时间,数据库依然会强制终止会话,并且回滚事务

dbms_shared_pool.purge工作原理猜测

联系:手机/微信(+86 17813235971) QQ(107644445)

标题:dbms_shared_pool.purge工作原理猜测

作者:惜分飞©版权所有[未经本人同意,不得以任何形式转载,否则有进一步追究法律责任的权利.]

思考为什么dbms_shared_pool.purge清理掉某条sql在shared pool中的信息,为什么当该sql再次执行的时候FIRST_LOAD_TIME时间没有发生改变
测试purge某条sql,再次加重该sql,FIRST_LOAD_TIME不变

SQL> select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from dual;
TO_CHAR(SYSDATE,'YY
-------------------
2013-02-12 16:44:00
SQL>  select SQL_ID,FIRST_LOAD_TIME from v$sql where sql_text like 'select to_char(sysdate,%dual';
SQL_ID        FIRST_LOAD_TIME
------------- --------------------------------------
46zkt5sgbxrxv 2013-02-12/16:43:59
SQL> SELECT ADDRESS,HASH_VALUE,SQL_TEXT FROM V$SQLAREA where sql_id='46zkt5sgbxrxv';
ADDRESS  HASH_VALUE
-------- ----------
SQL_TEXT
--------------------------------------------------------------------------------
2587FFAC  515825595
select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from dual
SQL>  exec dbms_shared_pool.purge('2587FFAC,515825595','C');
PL/SQL procedure successfully completed.
SQL> SELECT ADDRESS,HASH_VALUE,SQL_TEXT FROM V$SQLAREA where sql_id='46zkt5sgbxrxv';
no rows selected
SQL> !date
Tue Feb 12 16:55:15 CST 2013
SQL> select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from dual;
TO_CHAR(SYSDATE,'YY
-------------------
2013-02-12 16:55:23
SQL> select FIRST_LOAD_TIME FROM V$SQLAREA where sql_id='46zkt5sgbxrxv';
FIRST_LOAD_TIME
--------------------------------------
2013-02-12/16:43:59

这里可以看出来第一次执行sql语句的时候,FIRST_LOAD_TIME为2013-02-12/16:43:59,然后我使用dbms_shared_pool.purge”清除掉”了SQL语句在shared pool中的信息,但是当我再次执行执行相同的sql时候,查询发现FIRST_LOAD_TIME时间未发生改变.因为v$sql中对应的只有一张基表x$kglcursor_child,并没有where条件,而让记录不在v$sql中显示,证明是x$基表的东西发生了改变,而该基表是直接来自内存,从而个人猜测,oracle的dbms_shared_pool.purge是在shared pool该sql的内存某些部位增加了某些标记,从而使得该sql不能在v$sql等相关视图中显示,如果sql以前占用的内存区域没有被老化出shared pool,下次该sql再次访问的时候,优先启用该内存区域并修改相关值,从而出现了我们的FIRST_LOAD_TIME不改变的现象.

验证猜测

--session 1
SQL> exec dbms_shared_pool.purge('2587FFAC,515825595','C');
PL/SQL procedure successfully completed.
SQL> select FIRST_LOAD_TIME FROM V$SQLAREA where sql_id='46zkt5sgbxrxv';
no rows selected
SQL> declare
  2  begin
  3  FOR a IN  1..10000000
  4  LOOP
  5  EXECUTE IMMEDIATE 'insert into t_xifenfei values ('||a||')';
  6  END LOOP;
  7  commit;
  8  end;
  9  /
--session 2
SQL> select count(sql_text) from v$sql where sql_text like 'insert into t_xifenfei%'
  2  ;
COUNT(SQL_TEXT)
---------------
            444
SQL> /
COUNT(SQL_TEXT)
---------------
            445
SQL> /
COUNT(SQL_TEXT)
---------------
            444
SQL> /
COUNT(SQL_TEXT)
---------------
            442
--动态sql还在执行,但是共享池中的该sql不再增加,说明共享池已经满,
--部分历史的sql语句已经被刷新出共享池purge的sql语句肯定被老化出来了shared pool,然后再次执行该sql语句
--session 3
SQL> select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from dual;
TO_CHAR(SYSDATE,'YY
-------------------
2013-02-12 17:09:08
SQL> select SQL_ID,FIRST_LOAD_TIME from v$sql where sql_text like 'select to_char(sysdate,%dual';
SQL_ID        FIRST_LOAD_TIME
------------- --------------------------------------
46zkt5sgbxrxv 2013-02-12/17:09:07

这里可以看到当shared pool发生部分数据被刷出来之时,而且根据先进先出的原则,我们可以知道开始被purge的sql语句肯定被老化出shared pool,从而当再次执行相同sql的时候,生成了新的FIRST_LOAD_TIME,从而验证了部分猜测.
在此也补充另外一个朋友的咨询问题:在什么情况下FIRST_LOAD_TIME会发生改变,我认为是当sql语句占用的内存区域被老化出去,然后再进入内存的时候会发生改变,flush shared_pool实现效果和老化出来一样

SQL> select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from dual;
TO_CHAR(SYSDATE,'YY
-------------------
2013-02-12 17:09:08
SQL> select SQL_ID,FIRST_LOAD_TIME from v$sql where sql_text like 'select to_char(sysdate,%dual';
SQL_ID        FIRST_LOAD_TIME
------------- --------------------------------------
46zkt5sgbxrxv 2013-02-12/17:09:07
SQL> alter system flush shared_pool;
System altered.
SQL> select SQL_ID,FIRST_LOAD_TIME from v$sql where sql_text like 'select to_char(sysdate,%dual';
no rows selected
SQL> select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from dual;
TO_CHAR(SYSDATE,'YY
-------------------
2013-02-12 18:52:33
SQL> select SQL_ID,FIRST_LOAD_TIME from v$sql where sql_text like 'select to_char(sysdate,%dual';
SQL_ID        FIRST_LOAD_TIME
------------- --------------------------------------
46zkt5sgbxrxv 2013-02-12/18:52:33

因为shared pool的东西很复杂,我这里也只是大概的初步猜测,没有深入到系统级别dump之类的方法分析,如果有兴趣的朋友可以深入研究并探讨.

MON_MODS$和MON_MODS_ALL$统计DML操作次数

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标题:MON_MODS$和MON_MODS_ALL$统计DML操作次数

作者:惜分飞©版权所有[未经本人同意,不得以任何形式转载,否则有进一步追究法律责任的权利.]

*_TAB_MODIFICATIONS视图是用来记录自从收集统计信息后的DML(包括truncate)操作的次数,通过试验分析数据库是如何实现该功能,并且应用该功能来实现数据库自动收集功能(表变化比例决定是否收集统计信息)

SQL> select * from v$version;
BANNER
--------------------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - Production
PL/SQL Release 11.2.0.3.0 - Production
CORE    11.2.0.3.0      Production
TNS for Linux: Version 11.2.0.3.0 - Production
NLSRTL Version 11.2.0.3.0 - Production
SQL> DESC DBA_TAB_MODIFICATIONS
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 TABLE_OWNER                                        VARCHAR2(30)
 TABLE_NAME                                         VARCHAR2(30)
 PARTITION_NAME                                     VARCHAR2(30)
 SUBPARTITION_NAME                                  VARCHAR2(30)
 INSERTS                                            NUMBER
 UPDATES                                            NUMBER
 DELETES                                            NUMBER
 TIMESTAMP                                          DATE
 TRUNCATED                                          VARCHAR2(3)
 DROP_SEGMENTS                                      NUMBER
SQL> select text from dba_views where view_name='DBA_TAB_MODIFICATIONS';
TEXT
--------------------------------------------------------------------------------
select u.name, o.name, null, null,
       m.inserts, m.updates, m.deletes, m.timestamp,
       decode(bitand(m.flags,1),1,'YES','NO'),
       m.drop_segments
from sys.mon_mods_all$ m, sys.obj$ o, sys.tab$ t, sys.user$ u
where o.obj# = m.obj# and o.obj# = t.obj# and o.owner# = u.user#
union all
select u.name, o.name, o.subname, null,
       m.inserts, m.updates, m.deletes, m.timestamp,
       decode(bitand(m.flags,1),1,'YES','NO'),
       m.drop_segments
from sys.mon_mods_all$ m, sys.obj$ o, sys.user$ u
where o.owner# = u.user# and o.obj# = m.obj# and o.type#=19
union all
select u.name, o.name, o2.subname, o.subname,
       m.inserts, m.updates, m.deletes, m.timestamp,
       decode(bitand(m.flags,1),1,'YES','NO'),
       m.drop_segments
from sys.mon_mods_all$ m, sys.obj$ o, sys.tabsubpart$ tsp, sys.obj$ o2,
     sys.user$ u
where o.obj# = m.obj# and o.owner# = u.user# and
      o.obj# = tsp.obj# and o2.obj# = tsp.pobj#

这里很清楚,通过union all关联了三个select 语句,分别是查询普通表,分区表,子分区表,这里也可以看出来

对应基表

SQL> desc sys.mon_mods_all$
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 OBJ#                                               NUMBER
 INSERTS                                            NUMBER
 UPDATES                                            NUMBER
 DELETES                                            NUMBER
 TIMESTAMP                                          DATE
 FLAGS                                              NUMBER
 DROP_SEGMENTS                                      NUMBER
SQL> desc sys.mon_mods$
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 OBJ#                                               NUMBER
 INSERTS                                            NUMBER
 UPDATES                                            NUMBER
 DELETES                                            NUMBER
 TIMESTAMP                                          DATE
 FLAGS                                              NUMBER
 DROP_SEGMENTS                                      NUMBER

这两个基表结构完全相同,通过收集信息dml操作MON_MODS$然后记录MON_MODS_ALL$中

测试MON_MODS$和MON_MODS_ALL$关系

SQL> SELECT obj#,INSERTS,UPDATES,DELETES,FLAGS,TO_CHAR(TIMESTAMP,'YYYY-MM-DD HH24:MI:SS') LAST_TIME,
  2  DROP_SEGMENTS FROM sys.MON_MODS$ WHERE obj#=69900;
      OBJ#    INSERTS    UPDATES    DELETES      FLAGS LAST_TIME           DROP_SEGMENTS
---------- ---------- ---------- ---------- ---------- ------------------- -------------
     69900          0        297          0          0 2013-05-03 01:35:56             0
SQL> !date
Fri May  3 01:51:08 CST 2013
SQL> SELECT obj#,INSERTS,UPDATES,DELETES,FLAGS,TO_CHAR(TIMESTAMP,'YYYY-MM-DD HH24:MI:SS') LAST_TIME,
  2  DROP_SEGMENTS FROM sys.MON_MODS$ WHERE obj#=69900;
      OBJ#    INSERTS    UPDATES    DELETES      FLAGS LAST_TIME           DROP_SEGMENTS
---------- ---------- ---------- ---------- ---------- ------------------- -------------
     69900          0        297          0          0 2013-05-03 01:35:56             0
--15分钟未完全刷新mon_mod$
SQL> exec DBMS_STATS.FLUSH_DATABASE_MONITORING_INFO;
PL/SQL procedure successfully completed.
SQL> SELECT obj#,INSERTS,UPDATES,DELETES,FLAGS,TO_CHAR(TIMESTAMP,'YYYY-MM-DD HH24:MI:SS') LAST_TIME,
  2  DROP_SEGMENTS FROM sys.MON_MODS$ WHERE obj#=69900;
no rows selected
SQL> SELECT obj#,INSERTS,UPDATES,DELETES,FLAGS,TO_CHAR(TIMESTAMP,'YYYY-MM-DD HH24:MI:SS') LAST_TIME,
  2  DROP_SEGMENTS FROM sys.MON_MODS_ALL$ WHERE obj#=69900;
      OBJ#    INSERTS    UPDATES    DELETES      FLAGS LAST_TIME           DROP_SEGMENTS
---------- ---------- ---------- ---------- ---------- ------------------- -------------
     69900          0        323          0          0 2013-05-03 01:54:18             0

这里测试证明DBMS_STATS.FLUSH_DATABASE_MONITORING_INFO实现MON_MODS$刷新到MON_MODS_ALL$,但是未完全刷新MON_MODS$

测试MON_MODS_ALL$

SQL> create table t_xifenfei
  2  as
  3  select object_id,object_name from dba_objects;
Table created.
SQL> select object_id from user_objects where object_name='T_XIFENFEI';
 OBJECT_ID
----------
     76703
SQL> SELECT COUNT(*) FROM T_XIFENFEI;
  COUNT(*)
----------
     74806
--MON_MODS$无数据
SQL> SELECT INSERTS,UPDATES,DELETES,FLAGS,TO_CHAR(TIMESTAMP,'YYYY-MM-DD HH24:MI:SS') LAST_TIME,
  2  DROP_SEGMENTS FROM sys.MON_MODS$ WHERE OBJ#=76703;
no rows selected
--MON_MODS_ALL$中无数据
SQL> SELECT INSERTS,UPDATES,DELETES,FLAGS,TO_CHAR(TIMESTAMP,'YYYY-MM-DD HH24:MI:SS') LAST_TIME,
  2  DROP_SEGMENTS FROM sys.MON_MODS_ALL$ WHERE OBJ#=76703;
no rows selected
--UPDATE 操作
SQL> UPDATE T_XIFENFEI SET OBJECT_NAME='WWW.XIFENFEI.COM' WHERE MOD(OBJECT_ID,10)=0;
7474 rows updated.
SQL> COMMIT;
Commit complete.
--MON_MODS$和MON_MODS_ALL$中无数据,因为未从内存中刷新到MON_MODS$
SQL> SELECT INSERTS,UPDATES,DELETES,FLAGS,TO_CHAR(TIMESTAMP,'YYYY-MM-DD HH24:MI:SS') LAST_TIME,
  2  DROP_SEGMENTS FROM sys.MON_MODS$ WHERE OBJ#=76703;
no rows selected
SQL> SELECT INSERTS,UPDATES,DELETES,FLAGS,TO_CHAR(TIMESTAMP,'YYYY-MM-DD HH24:MI:SS') LAST_TIME,
  2  DROP_SEGMENTS FROM sys.MON_MODS_ALL$ WHERE OBJ#=76703;
no rows selected
--执行DBMS_STATS.FLUSH_DATABASE_MONITORING_INFO操作
SQL> exec DBMS_STATS.FLUSH_DATABASE_MONITORING_INFO;
PL/SQL procedure successfully completed.
--MON_MODS_ALL$中有数据
SQL> SELECT INSERTS,UPDATES,DELETES,FLAGS,TO_CHAR(TIMESTAMP,'YYYY-MM-DD HH24:MI:SS') LAST_TIME,
  2  DROP_SEGMENTS FROM sys.MON_MODS_ALL$ WHERE OBJ#=76703;
   INSERTS    UPDATES    DELETES      FLAGS LAST_TIME           DROP_SEGMENTS
---------- ---------- ---------- ---------- ------------------- -------------
         0       7474          0          0 2013-02-12 09:02:05             0
--这里统计的update数据和实际更新条数一致
--MON_MODS$中无数据,因为FLUSH_DATABASE_MONITORING_INFO刷新SGA中的dml和MON_MODS$到MON_MODS_ALL$中,并清空MON_MODS$
SQL> SELECT INSERTS,UPDATES,DELETES,FLAGS,TO_CHAR(TIMESTAMP,'YYYY-MM-DD HH24:MI:SS') LAST_TIME,
  2  DROP_SEGMENTS FROM sys.MON_MODS$ WHERE OBJ#=76703;
no rows selected
--DELETE操作
----session 1
SQL>  DELETE FROM T_XIFENFEI WHERE MOD(OBJECT_ID,3)=2;
24940 rows deleted.
----session 2
SQL> exec DBMS_STATS.FLUSH_DATABASE_MONITORING_INFO;
PL/SQL procedure successfully completed.
----session 1
SQL> SELECT INSERTS,UPDATES,DELETES,FLAGS,TO_CHAR(TIMESTAMP,'YYYY-MM-DD HH24:MI:SS') LAST_TIME,
  2  DROP_SEGMENTS FROM sys.MON_MODS_ALL$ WHERE OBJ#=76703;
   INSERTS    UPDATES    DELETES      FLAGS LAST_TIME           DROP_SEGMENTS
---------- ---------- ---------- ---------- ------------------- -------------
         0       7474      24940          0 2013-02-12 09:04:15             0
------这里可以看到,未提交的DML操作也统计到MON_MODS_ALL$中
----session 1
SQL> rollback;
Rollback complete.
----session 2
SQL> exec DBMS_STATS.FLUSH_DATABASE_MONITORING_INFO;
PL/SQL procedure successfully completed.
----session 2
SQL> SELECT INSERTS,UPDATES,DELETES,FLAGS,TO_CHAR(TIMESTAMP,'YYYY-MM-DD HH24:MI:SS') LAST_TIME,
  2  DROP_SEGMENTS FROM sys.MON_MODS_ALL$ WHERE OBJ#=76703;
   INSERTS    UPDATES    DELETES      FLAGS LAST_TIME           DROP_SEGMENTS
---------- ---------- ---------- ---------- ------------------- -------------
         0       7474      24940          0 2013-02-12 09:04:15             0
------通过这里可以rollback 操作也不能回滚MON_MODS_ALL$中未提交的事务
--再次DELETE操作
SQL> DELETE FROM T_XIFENFEI WHERE MOD(OBJECT_ID,5)=1;
14954 rows deleted.
----session 2
SQL> exec DBMS_STATS.FLUSH_DATABASE_MONITORING_INFO;
PL/SQL procedure successfully completed.
----session 1
SQL> SELECT INSERTS,UPDATES,DELETES,FLAGS,TO_CHAR(TIMESTAMP,'YYYY-MM-DD HH24:MI:SS') LAST_TIME,
  2  DROP_SEGMENTS FROM sys.MON_MODS_ALL$ WHERE OBJ#=76703;
   INSERTS    UPDATES    DELETES      FLAGS LAST_TIME           DROP_SEGMENTS
---------- ---------- ---------- ---------- ------------------- -------------
         0       7474      39894          0 2013-02-12 09:05:54             0
------DELETE操作在MON_MODS_ALL$中累加
--INSERT操作
SQL> insert into t_xifenfei select object_id,object_name from dba_objects;
74806 rows created.
SQL> commit;
Commit complete.
SQL> exec DBMS_STATS.FLUSH_DATABASE_MONITORING_INFO;
PL/SQL procedure successfully completed.
SQL> SELECT INSERTS,UPDATES,DELETES,FLAGS,TO_CHAR(TIMESTAMP,'YYYY-MM-DD HH24:MI:SS') LAST_TIME,
  2  DROP_SEGMENTS FROM sys.MON_MODS_ALL$ WHERE OBJ#=76703;
   INSERTS    UPDATES    DELETES      FLAGS LAST_TIME           DROP_SEGMENTS
---------- ---------- ---------- ---------- ------------------- -------------
     74806       7474      39894          0 2013-02-12 09:07:51             0
--收集统计信息
SQL> EXEC DBMS_STATS.gather_table_stats('CHF','T_XIFENFEI');
PL/SQL procedure successfully completed.
--MON_MODS_ALL$数据被清空
SQL> SELECT INSERTS,UPDATES,DELETES,FLAGS,TO_CHAR(TIMESTAMP,'YYYY-MM-DD HH24:MI:SS') LAST_TIME,
  2  DROP_SEGMENTS FROM sys.MON_MODS_ALL$ WHERE OBJ#=76703;
no rows selected
--TRUNCATE表被清空
SQL> truncate table t_xifenfei;
Table truncated.
SQL> exec DBMS_STATS.FLUSH_DATABASE_MONITORING_INFO;
PL/SQL procedure successfully completed.
SQL> SELECT INSERTS,UPDATES,DELETES,FLAGS,TO_CHAR(TIMESTAMP,'YYYY-MM-DD HH24:MI:SS') LAST_TIME,
  2  DROP_SEGMENTS FROM sys.MON_MODS_ALL$ WHERE OBJ#=76703;
   INSERTS    UPDATES    DELETES      FLAGS LAST_TIME           DROP_SEGMENTS
---------- ---------- ---------- ---------- ------------------- -------------
         0          0     134658          1 2013-02-12 09:29:49             0
----DELETES和FLAGS记录因为truncate操作而发生改变

从10GR2开始,数据库每15分钟就要把数据库的DML操作写入到mon_mods$(从SGA中写入到mon_mod$),但是这个写入过程1分钟,因此可能不是全部记录所有DML操作到mon_mods$.默认情况下,数据库每天会写入SGA中表的DML操作和mon_mods$到mon_mods_all$,也可以通过DBMS_STATS.FLUSH_DATABASE_MONITORING_INFO来人工写入到mon_mods_all$中,收集统计信息后mon_mods_all$表中信息清空

从执行效率上分析为什么SYSTEM不适宜存储业务数据

联系:手机/微信(+86 17813235971) QQ(107644445)

标题:从执行效率上分析为什么SYSTEM不适宜存储业务数据

作者:惜分飞©版权所有[未经本人同意,不得以任何形式转载,否则有进一步追究法律责任的权利.]

为什么不建议客户把业务数据存放到SYSTEM表空间中,一直想通过试验的数据来说明问题,今天见老熊的邮件和同事的blog(为什么不要把用户表存储到SYSTEM表空间)来说明把业务数据存放在SYSTEM表空间中效率的影响
数据库版本

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 Linux: Version 11.2.0.3.0 - Production
NLSRTL Version 11.2.0.3.0 - Production

创建测试环境

SQL> conn chf/xifenfei
Connected.
SQL> create table t_xifenfei_u(id number) tablespace users;
Table created.
SQL> create table t_xifenfei_s(id number) tablespace system;
Table created.
SQL>  select table_name,tablespace_name from user_tables;
TABLE_NAME                     TABLESPACE_NAME
------------------------------ ------------------------------
T_XIFENFEI_U                   USERS
T_XIFENFEI_S                   SYSTEM

非系统表空间测试

SQL> select STATISTIC#,NAME from v$statname where name='CPU used by this session';
STATISTIC# NAME
---------- ----------------------------------------------------------------
        17 CPU used by this session
SQL> select * from v$mystat where STATISTIC#=17;
       SID STATISTIC#      VALUE
---------- ---------- ----------
       189         17         33
SQL> set timing on
SQL> begin
  2  for i in 1..200000 loop
  3  insert into t_xifenfei_u values(i);
  4  end loop;
  5  end;
  6  /
PL/SQL procedure successfully completed.
Elapsed: 00:00:05.97
SQL> select * from v$mystat where STATISTIC#=17;
       SID STATISTIC#      VALUE
---------- ---------- ----------
       189         17        629
Elapsed: 00:00:00.00

测试结果显示,非系统表空间中的表插入200000条记录,使用时间为5.97秒;使用CPU为629-33=596

系统表空间测试

SQL> begin
  2  for i in 1..200000 loop
  3  insert into t_xifenfei_s values(i);
  4  end loop;
  5  end;
  6  /
PL/SQL procedure successfully completed.
Elapsed: 00:00:14.00
SQL> select * from v$mystat where STATISTIC#=17;
       SID STATISTIC#      VALUE
---------- ---------- ----------
       189         17       2019
Elapsed: 00:00:00.00

测试结果显示,对系统表空间中的表插入200000条记录,使用时间为14秒;使用CPU为2019-629=1390,基本上可以看出来无论是CPU消耗还是执行时间上,系统表空间占用都是非系统表空间两倍以上

分析原因

SQL> conn / as sysdba
Connected.
SQL> select * from (SELECT i.ksppinm NAME, i.ksppity TYPE, v.ksppstvl VALUE,
  2  v.ksppstdf isdefault FROM x$ksppi i, x$ksppcv v WHERE i.indx = v.indx AND
  3  i.ksppinm LIKE '/_%%' ESCAPE '/') where name like '%db_alw%';
NAME                                 TYPE VALUE           ISDEFAULT
------------------------------ ---------- --------------- ---------
_db_always_check_system_ts              1 TRUE            TRUE
SQL> alter system set "_db_always_check_system_ts"=false;
System altered.
SQL> conn chf/xifenfei
Connected.
SQL>  select * from v$mystat where STATISTIC#=17;
       SID STATISTIC#      VALUE
---------- ---------- ----------
       127         17          1
Elapsed: 00:00:00.01
SQL> begin
  2  for i in 1..200000 loop
  3  insert into t_xifenfei_s values(i);
  4  end loop;
  5  end;
  6  /
PL/SQL procedure successfully completed.
Elapsed: 00:00:06.03
SQL> select * from v$mystat where STATISTIC#=17;
       SID STATISTIC#      VALUE
---------- ---------- ----------
       127         17        582

通过这里可以发现,修改_db_always_check_system_ts=false之后,system表空间的操作基本上和非系统表空间所差无几(执行时间6.01秒,占用CPU 581=582-1)
在数据库默认情况下db_block_checking和db_block_checksum的值无论如何设置都不能对于SYSTEM表空间生效,也就是说SYSTEM表空间在没有修改_db_always_check_system_ts=false之前,对所有的块操作都要进行db_block_checking和db_block_checksum验证,从而使得数据块的操作效率较非SYSTEM表空间低下。对于一些插入较为频繁的aud$、FGA_LOG$、DEF$_AQCALL等表建议迁移到其他表空间

备注说明
DB_BLOCK_CHECKING

DB_BLOCK_CHECKING specifies whether or not Oracle performs block checking for database blocks.
Values:
OFF or FALSE
No block checking is performed for blocks in user tablespaces. However,
semantic block checking for SYSTEM tablespace blocks is always turned on.
LOW
Basic block header checks are performed after block contents change in memory
(for example, after UPDATE or INSERT statements, on-disk reads, or
inter-instance block transfers in Oracle RAC).
MEDIUM
All LOW checks and full semantic checks are performed for all objects except indexes
(whose contents can be reconstructed by a drop+rebuild on encountering a corruption).
FULL or TRUE
All LOW and MEDIUM checks and full semantic checks are performed for all objects.
Oracle checks a block by going through the data in the block, making sure it is logically
self-consistent. Block checking can often prevent memory and data corruption. Block checking
typically causes 1% to 10% overhead,depending on workload and the parameter value.
The more updates or inserts in a workload, the more expensive it is to turn on block checking.
You should set DB_BLOCK_CHECKING to FULL if the performance overhead is acceptable.
For backward compatibility, the use of FALSE (implying OFF) and TRUE (implying FULL) is preserved.

DB_BLOCK_CHECKSUM

DB_BLOCK_CHECKSUM determines whether DBWn and the direct loader will calculate a checksum
(a number calculated from all the bytes stored in the block) and store it in the cache header
of every data block when writing it to disk. Checksums are verified when a block is read -
only if this parameter is TYPICAL or FULL and the last write of the block stored a checksum.
In FULL mode, Oracle also verifies the checksum before a change application from update/delete
statements and recomputes it after the change is applied. In addition, Oracle gives every log block
a checksum before writing it to the current log.
Starting with Oracle Database 11g, most of the log block checksum is done by the generating foreground
processes, while the LGWR performs the rest of the work, for better CPU and cache efficiency.
Prior to Oracle Database 11g, the LGWR solely performed the log block checksum.
If this parameter is set to OFF, DBWn calculates checksums only for the SYSTEM tablespace,
but not for user tablespaces. In addition, no log checksum is performed when this parameter is set to OFF.
Checksums allow Oracle to detect corruption caused by underlying disks, storage systems, or I/O systems.
If set to FULL, DB_BLOCK_CHECKSUM also catches in-memory corruptions and stops them from making it to the disk.
Turning on this feature in TYPICAL mode causes only an additional 1% to 2% overhead. In the FULL mode it causes
4% to 5% overhead. Oracle recommends that you set DB_BLOCK_CHECKSUM to TYPICAL.
For backward compatibility the use of TRUE (implying TYPICAL) and FALSE (implying OFF) values is preserved.

使用oradebug hang住某个进程

联系:手机/微信(+86 17813235971) QQ(107644445)

标题:使用oradebug hang住某个进程

作者:惜分飞©版权所有[未经本人同意,不得以任何形式转载,否则有进一步追究法律责任的权利.]

在一次测试中,需要模拟在归档模式下,数据库发生多次redo切换而这些redo并未被归档的情景,一般来说这样的情况只有在归档目录满的时候会遇到.但是在日常测试中,这样的归档目录满的模拟不太现实,可以通过oradebug SUSPEND来实现该功能,让arcn进程挂起
配置log_archive_max_processes为1(可以配置多个,但是1个更加方便测试)

SQL> show parameter log_archive_max_processes;
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
log_archive_max_processes            integer     1

该配置可以在线修改,但是不重启数据库不一定完全生效(测试环境本来是4,修改为1之后,还有arc0和arc1进程)

查找arcn进程

[oracle@localhost trace]$ ps -ef|grep ora_arc
oracle    3686     1  0 21:07 ?        00:00:00 ora_arc0_test

oradebug进程(session 1)

SQL> oradebug  setospid  3686
Oracle pid: 57, Unix process pid: 3686, image: oracle@localhost.localdomain (ARC0)
SQL> oradebug SUSPEND
Statement processed.

alert日志

Tue Apr 16 21:09:42 2013
Unix process pid: 3686, image: oracle@localhost.localdomain (ARC0) flash frozen [ command #1 ]

切换日志(session 2)

SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence     53
Next log sequence to archive   55
Current log sequence           55
SQL> alter system switch logfile;
System altered.
SQL> /
System altered.
SQL> alter system checkpoint;
System altered.
SQL> set lines 134
SQL> col member for a40
SQL>   SELECT thread#,
  2           a.sequence#,a.ARCHIVED,
  3           a.group#,
  4           TO_CHAR (first_change#, '9999999999999999') "SCN",
  5           a.status,
  6           MEMBER
  7      FROM v$log a, v$logfile b
  8     WHERE a.group# = B.GROUP#
  9  ORDER BY a.sequence# DESC;
   THREAD#  SEQUENCE# ARC     GROUP# SCN               STATUS           MEMBER
---------- ---------- --- ---------- ----------------- ---------------- ----------------------------
         1         57 NO           3            261053 CURRENT          /data/oracle/oradata/test/redo03.log
         1         56 NO           2            261046 INACTIVE         /data/oracle/oradata/test/redo02.log
         1         55 NO           1            260856 INACTIVE         /data/oracle/oradata/test/redo01.log
SQL> alter system switch logfile;--hang住

此时alert日志

Tue Apr 16 21:10:19 2013
Thread 1 advanced to log sequence 56 (LGWR switch)
  Current log# 2 seq# 56 mem# 0: /data/oracle/oradata/test/redo02.log
Tue Apr 16 21:10:36 2013
Thread 1 advanced to log sequence 57 (LGWR switch)
  Current log# 3 seq# 57 mem# 0: /data/oracle/oradata/test/redo03.log
Tue Apr 16 21:13:13 2013
ORACLE Instance test - Can not allocate log, archival required
Thread 1 cannot allocate new log, sequence 58
All online logs needed archiving
  Current log# 3 seq# 57 mem# 0: /data/oracle/oradata/test/redo03.log

oradebug RESUME(session 1)

SQL> oradebug RESUME
Statement processed.

alert日志

Tue Apr 16 21:14:23 2013
Unix process pid: 3686, image: oracle@localhost.localdomain (ARC0) resumed
Archived Log entry 2 added for thread 1 sequence 55 ID 0x7dd4ccb7 dest 1:
Archived Log entry 3 added for thread 1 sequence 56 ID 0x7dd4ccb7 dest 1:

hang住会话继续执行(session 2)

SQL> alter system switch logfile;
System altered.

ORACLE 12C RMAN recover table

联系:手机/微信(+86 17813235971) QQ(107644445)

标题:ORACLE 12C RMAN recover table

作者:惜分飞©版权所有[未经本人同意,不得以任何形式转载,否则有进一步追究法律责任的权利.]

12c的rman有了很大的增强,其中一个亮点就是可以进行table 级别的恢复,本试验测试了rman基于时间点恢复一个被删除表的操作过程
数据库版本

SQL> select * from v$version;
BANNER                                                                               CON_ID
-------------------------------------------------------------------------------- ----------
Oracle Database 12c Enterprise Edition Release 12.1.0.0.2 - 64bit                         0
PL/SQL Release 12.1.0.0.2                                                                 0
CORE    12.1.0.0.2                                                                        0
TNS for Linux: Version 12.1.0.0.2                                                         0
NLSRTL Version 12.1.0.0.2                                                                 0

创建表并插入数据

SQL> select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from dual;
TO_CHAR(SYSDATE,'YY
-------------------
2013-01-17 18:37:07
SQL> create table t_xifenfei(id number,insert_time date);
Table created.
SQL> insert into t_xifenfei values(1,sysdate);
1 row created.
SQL> commit;
Commit complete.
SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence     53
Next log sequence to archive   55
Current log sequence           55
SQL> select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from dual;
TO_CHAR(SYSDATE,'YY
-------------------
2013-01-17 18:37:55

备份数据库

RMAN> backup  as compressed backupset database  format '/tmp/xifenfei_db_%U';
Starting backup at 17-JAN-13
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=30 device type=DISK
channel ORA_DISK_1: starting compressed full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00001 name=/u01/app/oracle/oradata/xifenfei/system01.dbf
input datafile file number=00002 name=/u01/app/oracle/oradata/xifenfei/sysaux01.dbf
input datafile file number=00003 name=/u01/app/oracle/oradata/xifenfei/undotbs01.dbf
input datafile file number=00005 name=/u01/app/oracle/oradata/xifenfei/xifenfei01.dbf
input datafile file number=00004 name=/u01/app/oracle/oradata/xifenfei/users01.dbf
channel ORA_DISK_1: starting piece 1 at 17-JAN-13
channel ORA_DISK_1: finished piece 1 at 17-JAN-13
piece handle=/tmp/xifenfei_db_07nvln1g_1_1 tag=TAG20130117T183839 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:01:15
channel ORA_DISK_1: starting compressed full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
including current control file in backup set
including current SPFILE in backup set
channel ORA_DISK_1: starting piece 1 at 17-JAN-13
channel ORA_DISK_1: finished piece 1 at 17-JAN-13
piece handle=/tmp/xifenfei_db_08nvln3r_1_1 tag=TAG20130117T183839 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:03
Finished backup at 17-JAN-13

插入数据继续测试

SQL> insert into t_xifenfei values(2,sysdate);
1 row created.
SQL> commit;
Commit complete.
SQL> alter system switch logfile;
System altered.
SQL> alter system switch logfile;
System altered.
SQL> insert into t_xifenfei values(3,sysdate);
1 row created.
SQL> insert into t_xifenfei values(4,sysdate);
1 row created.
SQL> commit;
Commit complete.
SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence     55
Next log sequence to archive   57
Current log sequence           57
SQL> select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from dual;
TO_CHAR(SYSDATE,'YY
-------------------
2013-01-17 18:41:17
SQL> select id,to_char(insert_time,'yyyy-mm-dd hh24:mi:ss') from t_xifenfei;
        ID TO_CHAR(INSERT_TIME
---------- -------------------
         1 2013-01-17 18:37:22
         2 2013-01-17 18:40:37
         3 2013-01-17 18:40:58
         4 2013-01-17 18:40:59

删除测试表

SQL> drop table t_xifenfei purge;
Table dropped.
SQL> select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from dual;
TO_CHAR(SYSDATE,'YY
-------------------
2013-01-17 18:41:36

rman recover table

[oracle@Lunar tmp]$ rman target sys/xifenfei log=/tmp/recover_table.log
RMAN> RECOVER TABLE XFF."T_XIFENFEI"
until time  "to_date('2013-01-17 18:41:17','yyyy-mm-dd hh24:mi:ss')"
AUXILIARY DESTINATION '/tmp/recovertable'
REMAP TABLE 'XFF'.'T_XIFENFEI':'T_XIFENFEI_NEW';
--recover table XFF.T_XIFENFEI data impdp into XFF.T_XIFENFEI_NEW

验证数据库

SQL> select id,to_char(insert_time,'yyyy-mm-dd hh24:mi:ss') from t_xifenfei_new;
        ID TO_CHAR(INSERT_TIME
---------- -------------------
         1 2013-01-17 18:37:22
         2 2013-01-17 18:40:37
         3 2013-01-17 18:40:58
         4 2013-01-17 18:40:59

补充说明
1.rman recover table 必须使用sys用户登录,而不能使用/,因为12c默认有backup用户
2.rman recover table 需要还原system,undo,sysaux表空间,需要还原表所在表空间,和expdp导出文件空间,所以需要额外空间较大
3.整体恢复过程是:还原system,undo,sysaux表空间,然后read only数据库,然后重启数据库还原表所在表空间,然后expdp导出表,根据需要决定是否导入表到数据库
4.完整的rman recover table执行过程脚本recover_table

Swingbench简单使用

联系:手机/微信(+86 17813235971) QQ(107644445)

标题:Swingbench简单使用

作者:惜分飞©版权所有[未经本人同意,不得以任何形式转载,否则有进一步追究法律责任的权利.]

Swingbench是一款很不错的oracle压力测试工具,使用比较简单,而且很效果比较明显,可以满足在一些简单的测试案例中的需求,这里大概的写了主要的Swingbench测试过程中的一些注意事项
1.相关网站
Swingbench
2.上传服务器并解压

--整体目录
[oracle@localhost swingbench]$ ll
total 484
drwxr-xr-x. 3 oracle dba   4096 Mar 26 15:54 bin
drwxr-xr-x. 2 oracle dba   4096 Mar 26 15:48 configs
drwxr-xr-x. 2 oracle dba   4096 Jun 11  2010 launcher
drwxr-xr-x. 3 oracle dba   4096 Dec  9  2011 lib
drwxr-xr-x. 2 oracle dba   4096 Mar  3  2010 log
-rwx------. 1 oracle dba   1768 Feb 15  2011 README.txt
drwxr-xr-x. 3 oracle dba   4096 Dec  9  2011 source
drwxr-xr-x. 2 oracle dba   4096 Mar 26 15:38 sql
-rw-r--r--. 1 oracle dba    848 Mar 26 11:02 swingbench.env
-rw-r--r--. 1 oracle dba 454110 Feb 15  2011 swingbenchFAQ.pdf
drwx------. 3 oracle dba   4096 Dec  8  2011 winbin
--动态库
[oracle@localhost lib]$ ll
total 14896
-rw-r--r--. 1 oracle dba   999966 Dec  9  2011 ant.jar
drwxr-xr-x. 2 oracle dba     4096 Dec  9  2011 launcher
-rw-r--r--. 1 oracle dba  2152849 Dec  9  2011 ojdbc6.jar
-rw-r--r--. 1 oracle dba    70569 Dec  9  2011 ons.jar
-rw-r--r--. 1 oracle dba    20349 Dec  9  2011 simplefan.jar
-rw-r--r--. 1 oracle dba 11512178 Dec  9  2011 swingbench.jar
-rw-r--r--. 1 oracle dba   479413 Dec  9  2011 ucp.jar
--相关执行文件和初始化*.xml文件等
[oracle@localhost bin]$ ll
total 192
-rwxr-xr-x. 1 oracle dba    106 Nov 17  2010 bmcompare
-rwx------. 1 oracle dba   4456 Apr 19  2010 ccconfig.xml
-rwxr-xr-x. 1 oracle dba    120 Nov 17  2010 ccwizard
-rwx------. 1 oracle dba   4086 Jul 27  2010 ccwizard.xml
-rwxr-xr-x. 1 oracle dba    106 Nov 17  2010 charbench
-rwxr-xr-x. 1 oracle dba    118 Nov 17  2010 clusteroverview
-rw-r--r--. 1 oracle dba   1740 Jul 27  2010 clusteroverview.xml
-rwxr-xr-x. 1 oracle dba    110 Nov 17  2010 coordinator
drwxr-xr-x. 2 oracle dba   4096 Dec  8  2011 data
-rw-r--r--. 1 oracle dba 113698 Nov  2  2011 debug.log
-rwxr-xr-x. 1 oracle dba    106 Nov 17  2010 minibench
-rwxr-xr-x. 1 oracle dba    120 Nov 17  2010 oewizard
-rwx------. 1 oracle dba   3279 Jul 27  2010 oewizard.xml
-rw-r--r--. 1 oracle dba   2790 Feb 15  2011 results.xml
-rwxr-xr-x. 1 oracle dba    128 Nov 17  2010 shwizard
-rwx------. 1 oracle dba   2499 Aug 28  2010 shwizard.xml
-rwxr-xr-x. 1 oracle dba    108 Nov 17  2010 swingbench
-rwx------. 1 oracle dba   5766 Mar 26 15:29 swingconfig.xml
-rw-r--r--. 1 oracle dba    241 Mar 26 11:56 wizardlog.xml
--执行相关*.xml配置文件
[oracle@localhost configs]$ ll
total 36
-rwx------. 1 oracle dba 4714 Mar 27 10:02 ccconfig.xml
-rwx------. 1 oracle dba 3950 Nov  8  2011 oeconfig.xml
-rwx------. 1 oracle dba 3774 Nov  8  2011 shconfig.xml
-rwx------. 1 oracle dba 5009 Mar 27 10:15 soeconfig.xml
-rwx------. 1 oracle dba 3198 Nov  8  2011 spconfig.xml
-rwx------. 1 oracle dba 3074 Mar 23  2010 stresstest.xml

3.编辑环境变量

--自己编辑生成,然后使用.执行
vi swingbench.env
#!/bin/bash
--note:官方要求java 1.6,oracle 11g自带1.5可以执行
export JAVAHOME=/data/oracle/product/11.2.0/dbhome_1/jdk
export SWINGHOME=/swingbench
export ORACLE_HOME=/data/oracle/product/11.2.0/dbhome_1
export LD_LIBRARY_PATH=${LD_LIBRARY_PATH}:$ORACLE_HOME/lib:$SWINGHOME/lib
export CLASSPATH=$JAVAHOME/lib/rt.jar:$JAVAHOME/lib/tools.jar:${SWINGHOME}/lib/swingbench.jar
export CLASSPATH=$CALSSPATH:${SWINGHOME}/lib/ojdbc6.jar:${SWINGHOME}/lib/ant.jar:ucp.jar
export CLASSPATH=$CLASSPATH:$ORACLE_HOME/jdbc/lib/ojdbc14.jar:$ORACLE_HOME/opmn/lib/ons.jar
export CLASSPATH=$CLASSPATH:$ORACLE_HOME/jdbc/lib/ojdbc5.jar

4.初始化数据

--初始化sh数据
[oracle@localhost bin]$ ll sh*
-rwxr-xr-x. 1 oracle dba  128 Nov 17  2010 shwizard
-rwx------. 1 oracle dba 2499 Aug 28  2010 shwizard.xml
--初始化soe数据
[oracle@localhost bin]$ ll oe*
-rwxr-xr-x. 1 oracle dba  120 Nov 17  2010 oewizard
-rwx------. 1 oracle dba 3279 Jul 27  2010 oewizard.xml
--初始化cc数据
[oracle@localhost bin]$ ll ccwizard*
-rwxr-xr-x. 1 oracle dba  120 Nov 17  2010 ccwizard
-rwx------. 1 oracle dba 4086 Jul 27  2010 ccwizard.xml

5.执行压力测试

--执行sh
[oracle@localhost bin]$ ./swingbench -c /swingbench/configs/shconfig.xml
--执行soe
[oracle@localhost bin]$ ./swingbench -c /swingbench/configs/soeconfig.xml
--执行cc
[oracle@localhost bin]$ ./swingbench -c /swingbench/configs/ccconfig.xml

6.测试结果
为了能够收集系统的io和cpu,需要登录系统(configuration–>connect pooling–>distributed controls)

bbed模拟提交事务二之屏蔽smon回滚事务

联系:手机/微信(+86 17813235971) QQ(107644445)

标题:bbed模拟提交事务二之屏蔽smon回滚事务

作者:惜分飞©版权所有[未经本人同意,不得以任何形式转载,否则有进一步追究法律责任的权利.]

在上一篇修改datablock itl(bbed模拟提交事务一之修改itl)的基础之上,本篇实现修改undo segment header中的相关事务槽信息,从而屏蔽数据库在重启或者进程异常的时候,smon的回滚操作,从而比较完美的实现了手工提交数据库事务
update table and uncommit(session 1)

SQL> select distinct
  2  dbms_rowid.rowid_relative_fno(rowid) rel_fno,
  3  dbms_rowid.rowid_block_number(rowid) block_no
  4  from chf.t_xifenfei;
   REL_FNO   BLOCK_NO
---------- ----------
         4         28
SQL> select * from chf.t_xifenfei;
 OBJECT_ID OBJECT_NAME
---------- --------------------
        20 xifenfei.com
        44 xifenfei.com
        28 xifenfei.com
        15 xifenfei.com
        29 xifenfei.com
         3 xifenfei.com
        25 xifenfei.com
        39 xifenfei.com
        51 xifenfei.com
        26 xifenfei.com
        17 xifenfei.com
        13 xifenfei.com
         9 xifenfei.com
        41 xifenfei.com
        48 I_CON1
        38 I_OBJ3
         7 I_TS#
        53 I_CDEF4
        19 IND$
19 rows selected.
SQL> update chf.t_xifenfei set object_name='orasos.com' where rownum<10;
9 rows updated.
SQL> select * from chf.t_xifenfei;
 OBJECT_ID OBJECT_NAME
---------- --------------------
        20 orasos.com
        44 orasos.com
        28 orasos.com
        15 orasos.com
        29 orasos.com
         3 orasos.com
        25 orasos.com
        39 orasos.com
        51 orasos.com
        26 xifenfei.com
        17 xifenfei.com
        13 xifenfei.com
         9 xifenfei.com
        41 xifenfei.com
        48 I_CON1
        38 I_OBJ3
         7 I_TS#
        53 I_CDEF4
        19 IND$
19 rows selected.

dump undo header(session 2)

SQL> alter system flush buffer_cache;
System altered.
SQL> alter system checkpoint;
System altered.
SQL> SELECT XIDUSN,XIDSLOT,XIDSQN,UBAFIL,UBABLK,UBASQN,UBAREC FROM v$transaction;
    XIDUSN    XIDSLOT     XIDSQN     UBAFIL     UBABLK     UBASQN     UBAREC
---------- ---------- ---------- ---------- ---------- ---------- ----------
         1         13        367          2       1126        362         32
SQL>  alter system dump undo header "_SYSSMU1$";
System altered.
index  state cflags  wrap#    uel         scn            dba     parent-xid          nub       stmt_num       cmt
------------------------------------------------------------------------------------------------------------------
   …………
0x0c    9    0x00  0x016e  0x0029  0x0b2c.c02d1f6a  0x00800464  0x0000.000.00000000  0x00000001   0x00000000  1358813163
0x0d   10    0x80  0x016f  0x0002  0x0b2c.c02d7b15  0x00800466  0x0000.000.00000000  0x00000001   0x00000000  0
0x0e    9    0x00  0x016f  0x000f  0x0b2c.c02d2ae2  0x00800466  0x0000.000.00000000  0x00000001   0x00000000  1358820065
   …………

通过结合dump undo header 中的TRN TBL的state为10的为active事务,然后结合scn/dba等信息,
来确定是哪条记录是需要我们修改.然后通过find命令快速定位到0x0d这条记录,然后进行修改

通过结合bbed的dump命令得出16进制数据分析得出如下结论

--index 0x0c
6e01        0000 64048000      6a1f2dc0 2c0b0000      09       00          2900
0000000000000000            00000000          01000000     ebd7fd50(1358813163注意存储顺序)
--index 0x0d
6f01  wrap# 0000 66048000 dba  157b2dc0 2c0b0000 scn  0a state 80  cflags  0200 uel
0000000000000000 parent-xid 00000000 stmt_num 01000000 nub 00000000 cmt
--index 0x0e
6f01        0000 66048000      e22a2dc0 2c0b0000      09       00          0f00
0000000000000000            00000000          01000000     e1f2fd50(1358820065)

bbed modify undo segment header(session 2)

BBED> f /x 0a80
 File: /u01/oracle/oradata/XFF/undotbs01.dbf (0)
 Block: 9                Offsets: 6736 to 6751           Dba:0x00000000
------------------------------------------------------------------------
 0a800200 00000000 00000000 00000000
 <32 bytes per line>
BBED> m /x 0900
Warning: contents of previous BIFILE will be lost. Proceed? (Y/N) y
 File: /u01/oracle/oradata/XFF/undotbs01.dbf (0)
 Block: 9                Offsets: 6736 to 6751           Dba:0x00000000
------------------------------------------------------------------------
 09000200 00000000 00000000 00000000
 <32 bytes per line>
BBED> sum apply
Check value for File 0, Block 9:
current = 0xecdd, required = 0xecdd

bbed modify data block itl(session 2)

struct ktbbhitl[0], 24 bytes             @44
      struct ktbitxid, 8 bytes              @44
         ub2 kxidusn                        @44       0x0001
         ub2 kxidslt                        @46       0x000d
         ub4 kxidsqn                        @48       0x0000016f
      struct ktbituba, 8 bytes              @52
         ub4 kubadba                        @52       0x00800466
         ub2 kubaseq                        @56       0x016a
         ub1 kubarec                        @58       0x20
      ub2 ktbitflg                          @60       0x0009 (NONE)
      union _ktbitun, 2 bytes               @62
         b2 _ktbitfsc                       @62       18
         ub2 _ktbitwrp                      @62       0x0012
      ub4 ktbitbas                          @64       0x00000000
BBED> m /x 0080 offset 60
Warning: contents of previous BIFILE will be lost. Proceed? (Y/N) y
 File: /u01/oracle/oradata/XFF/users01.dbf (0)
 Block: 28               Offsets:   60 to  571           Dba:0x00000000
------------------------------------------------------------------------
 00801200 00000000 09002a00 36020000
 <32 bytes per line>
BBED> sum apply
Check value for File 0, Block 28:
current = 0xccf1, required = 0xccf1

restart db and select table(session 3)

SQL> shutdown abort
ORACLE instance shut down.
SQL> startup
ORACLE instance started.
Total System Global Area  306184192 bytes
Fixed Size                  1267164 bytes
Variable Size             109054500 bytes
Database Buffers          188743680 bytes
Redo Buffers                7118848 bytes
Database mounted.
Database opened.
SQL> col object_name for a20
SQL> set pages 100
SQL> select * from chf.t_xifenfei;
 OBJECT_ID OBJECT_NAME
---------- --------------------
        20 orasos.com
        44 orasos.com
        28 orasos.com
        15 orasos.com
        29 orasos.com
         3 orasos.com
        25 orasos.com
        39 orasos.com
        51 orasos.com
        26 xifenfei.com
        17 xifenfei.com
        13 xifenfei.com
         9 xifenfei.com
        41 xifenfei.com
        48 I_CON1
        38 I_OBJ3
         7 I_TS#
        53 I_CDEF4
        19 IND$
19 rows selected.

到此证明,通过修改undo segment header中的state和cflags实现数据库启动不回滚未提交事务;通过修改datablock itl实现数据库在访问未提交数据块时候不访问undo。从而整体上较完美的实现了手工提交一个事务(数据库提交一个事务涉及的方方面面较为复杂,这里只是通过修改最核心的两部分来大致模拟提交事务)