Oracle – 第21页 – Database SOS

v$datafile.enabled相关值说明

自认为对v$datafile视图算比较了解,但是今天看到一网友的v$datafile.enabled=DISABLED,我一时没有想出来是为什么,这里通过试验对v$datafile.enabled各种情况进行了试验并简单说明scn的变化情况
模拟环境(READ WRITE)

SQL> alter tablespace users add datafile '/u01/oracle/oradata/XFF/users02.dbf' size 10m;
Tablespace altered.
SQL> select file#,ts#,CHECKPOINT_CHANGE#,enabled,status,name from v$datafile;
     FILE#        TS# CHECKPOINT_CHANGE# ENABLED    STATUS  NAME
---------- ---------- ------------------ ---------- ------- ---------------------------------------
         1          0             456727 READ WRITE SYSTEM  /u01/oracle/oradata/XFF/system01.dbf
         2          1             456727 READ WRITE ONLINE  /u01/oracle/oradata/XFF/undotbs01.dbf
         3          2             456727 READ WRITE ONLINE  /u01/oracle/oradata/XFF/sysaux01.dbf
         4          4             456727 READ WRITE ONLINE  /u01/oracle/oradata/XFF/users01.dbf
         5          4             458322 READ WRITE ONLINE  /u01/oracle/oradata/XFF/users02.dbf
QL> select file#,status, CHECKPOINT_CHANGE# from v$datafile_header;
     FILE# STATUS  CHECKPOINT_CHANGE#
---------- ------- ------------------
         1 ONLINE              456727
         2 ONLINE              456727
         3 ONLINE              456727
         4 ONLINE              456727
         5 ONLINE              458322

加入数据文件scn不一样是因为:加入数据文件的时候,使用是当前scn,而数据库未做checkpoint,所以出现数据文件scn不一致现象

datafile offline(READ WRITE)

SQL> alter database datafile 5 offline;
Database altered.
SQL> alter system checkpoint;
System altered.
SQL> /
System altered.
SQL> select file#,status, CHECKPOINT_CHANGE# from v$datafile_header;
     FILE# STATUS  CHECKPOINT_CHANGE#
---------- ------- ------------------
         1 ONLINE              458392
         2 ONLINE              458392
         3 ONLINE              458392
         4 ONLINE              458392
         5 OFFLINE             458322
SQL> select file#,ts#,CHECKPOINT_CHANGE#,enabled,status,name from v$datafile;
     FILE#        TS# CHECKPOINT_CHANGE# ENABLED    STATUS  NAME
---------- ---------- ------------------ ---------- ------- ----------------------------------------
         1          0             458392 READ WRITE SYSTEM  /u01/oracle/oradata/XFF/system01.dbf
         2          1             458392 READ WRITE ONLINE  /u01/oracle/oradata/XFF/undotbs01.dbf
         3          2             458392 READ WRITE ONLINE  /u01/oracle/oradata/XFF/sysaux01.dbf
         4          4             458392 READ WRITE ONLINE  /u01/oracle/oradata/XFF/users01.dbf
         5          4             458322 READ WRITE RECOVER /u01/oracle/oradata/XFF/users02.dbf

这里可以看出来数据文件offline之后,v$datafile.enabled依然是READ WRITE,但是该数据文件的scn不再变化

tablespace offline(DISABLED)

SQL> recover datafile 5;
Media recovery complete.
SQL> alter database datafile 5 online;
Database altered.
SQL>  select file#,ts#,CHECKPOINT_CHANGE#,enabled,status,name from v$datafile;
     FILE#        TS# CHECKPOINT_CHANGE# ENABLED    STATUS  NAME
---------- ---------- ------------------ ---------- ------- --------------------------------------
         1          0             458392 READ WRITE SYSTEM  /u01/oracle/oradata/XFF/system01.dbf
         2          1             458392 READ WRITE ONLINE  /u01/oracle/oradata/XFF/undotbs01.dbf
         3          2             458392 READ WRITE ONLINE  /u01/oracle/oradata/XFF/sysaux01.dbf
         4          4             458392 READ WRITE ONLINE  /u01/oracle/oradata/XFF/users01.dbf
         5          4             458430 READ WRITE ONLINE  /u01/oracle/oradata/XFF/users02.dbf
SQL> select file#,status, CHECKPOINT_CHANGE# from v$datafile_header;
     FILE# STATUS  CHECKPOINT_CHANGE#
---------- ------- ------------------
         1 ONLINE              458392
         2 ONLINE              458392
         3 ONLINE              458392
         4 ONLINE              458392
         5 ONLINE              458430
SQL> alter system checkpoint;
System altered.
SQL> select file#,ts#,CHECKPOINT_CHANGE#,enabled,status,name from v$datafile;
     FILE#        TS# CHECKPOINT_CHANGE# ENABLED    STATUS  NAME
---------- ---------- ------------------ ---------- ------- ---------------------------------------
         1          0             458443 READ WRITE SYSTEM  /u01/oracle/oradata/XFF/system01.dbf
         2          1             458443 READ WRITE ONLINE  /u01/oracle/oradata/XFF/undotbs01.dbf
         3          2             458443 READ WRITE ONLINE  /u01/oracle/oradata/XFF/sysaux01.dbf
         4          4             458443 READ WRITE ONLINE  /u01/oracle/oradata/XFF/users01.dbf
         5          4             458443 READ WRITE ONLINE  /u01/oracle/oradata/XFF/users02.dbf
SQL> select file#,status, CHECKPOINT_CHANGE# from v$datafile_header;
     FILE# STATUS  CHECKPOINT_CHANGE#
---------- ------- ------------------
         1 ONLINE              458443
         2 ONLINE              458443
         3 ONLINE              458443
         4 ONLINE              458443
         5 ONLINE              458443
SQL> alter tablespace users offline;
Tablespace altered.
SQL> alter system checkpoint;
System altered.
SQL> /
System altered.
SQL> select file#,ts#,CHECKPOINT_CHANGE#,enabled,status,name from v$datafile;
     FILE#        TS# CHECKPOINT_CHANGE# ENABLED    STATUS  NAME
---------- ---------- ------------------ ---------- ------- --------------------------------------
         1          0             458497 READ WRITE SYSTEM  /u01/oracle/oradata/XFF/system01.dbf
         2          1             458497 READ WRITE ONLINE  /u01/oracle/oradata/XFF/undotbs01.dbf
         3          2             458497 READ WRITE ONLINE  /u01/oracle/oradata/XFF/sysaux01.dbf
         4          4             458457 DISABLED   OFFLINE /u01/oracle/oradata/XFF/users01.dbf
         5          4             458457 DISABLED   OFFLINE /u01/oracle/oradata/XFF/users02.dbf
SQL> select file#,status, CHECKPOINT_CHANGE# from v$datafile_header;
     FILE# STATUS  CHECKPOINT_CHANGE#
---------- ------- ------------------
         1 ONLINE              458497
         2 ONLINE              458497
         3 ONLINE              458497
         4 OFFLINE                  0
         5 OFFLINE                  0
SQL> alter system checkpoint;
System altered.
SQL> /
System altered.
SQL> select file#,ts#,CHECKPOINT_CHANGE#,enabled,status,name from v$datafile;
     FILE#        TS# CHECKPOINT_CHANGE# ENABLED    STATUS  NAME
---------- ---------- ------------------ ---------- ------- --------------------------------------------------
         1          0             458512 READ WRITE SYSTEM  /u01/oracle/oradata/XFF/system01.dbf
         2          1             458512 READ WRITE ONLINE  /u01/oracle/oradata/XFF/undotbs01.dbf
         3          2             458512 READ WRITE ONLINE  /u01/oracle/oradata/XFF/sysaux01.dbf
         4          4             458457 DISABLED   OFFLINE /u01/oracle/oradata/XFF/users01.dbf
         5          4             458457 DISABLED   OFFLINE /u01/oracle/oradata/XFF/users02.dbf
SQL> select file#,status, CHECKPOINT_CHANGE# from v$datafile_header;
     FILE# STATUS  CHECKPOINT_CHANGE#
---------- ------- ------------------
         1 ONLINE              458512
         2 ONLINE              458512
         3 ONLINE              458512
         4 OFFLINE                  0
         5 OFFLINE                  0
SQL> alter tablespace users online;
Tablespace altered.
SQL> select file#,status, CHECKPOINT_CHANGE# from v$datafile_header;
     FILE# STATUS  CHECKPOINT_CHANGE#
---------- ------- ------------------
         1 ONLINE              458512
         2 ONLINE              458512
         3 ONLINE              458512
         4 ONLINE              458526
         5 ONLINE              458526
SQL> select file#,ts#,CHECKPOINT_CHANGE#,enabled,status,name from v$datafile;
     FILE#        TS# CHECKPOINT_CHANGE# ENABLED    STATUS  NAME
---------- ---------- ------------------ ---------- ------- --------------------------------------------------
         1          0             458512 READ WRITE SYSTEM  /u01/oracle/oradata/XFF/system01.dbf
         2          1             458512 READ WRITE ONLINE  /u01/oracle/oradata/XFF/undotbs01.dbf
         3          2             458512 READ WRITE ONLINE  /u01/oracle/oradata/XFF/sysaux01.dbf
         4          4             458526 READ WRITE ONLINE  /u01/oracle/oradata/XFF/users01.dbf
         5          4             458526 READ WRITE ONLINE  /u01/oracle/oradata/XFF/users02.dbf
SQL> alter system checkpoint;
System altered.
SQL> select file#,ts#,CHECKPOINT_CHANGE#,enabled,status,name from v$datafile;
     FILE#        TS# CHECKPOINT_CHANGE# ENABLED    STATUS  NAME
---------- ---------- ------------------ ---------- ------- --------------------------------------------------
         1          0             458551 READ WRITE SYSTEM  /u01/oracle/oradata/XFF/system01.dbf
         2          1             458551 READ WRITE ONLINE  /u01/oracle/oradata/XFF/undotbs01.dbf
         3          2             458551 READ WRITE ONLINE  /u01/oracle/oradata/XFF/sysaux01.dbf
         4          4             458551 READ WRITE ONLINE  /u01/oracle/oradata/XFF/users01.dbf
         5          4             458551 READ WRITE ONLINE  /u01/oracle/oradata/XFF/users02.dbf
SQL> select file#,status, CHECKPOINT_CHANGE# from v$datafile_header;
     FILE# STATUS  CHECKPOINT_CHANGE#
---------- ------- ------------------
         1 ONLINE              458551
         2 ONLINE              458551
         3 ONLINE              458551
         4 ONLINE              458551
         5 ONLINE              458551

以上部分证明：
1.online datafile也不触发database checkpoint
2.tablespace offline后v$datafile.enabled为DISABLED
3.控制文件对应表空间scn不再变化,datafile header scn变为0
4.tablespace online不需要recover

tablespace read only(READ ONLY)

SQL> alter tablespace users read only;
Tablespace altered.
SQL> select file#,ts#,CHECKPOINT_CHANGE#,enabled,status,name from v$datafile;
     FILE#        TS# CHECKPOINT_CHANGE# ENABLED    STATUS  NAME
---------- ---------- ------------------ ---------- ------- --------------------------------------------------
         1          0             458551 READ WRITE SYSTEM  /u01/oracle/oradata/XFF/system01.dbf
         2          1             458551 READ WRITE ONLINE  /u01/oracle/oradata/XFF/undotbs01.dbf
         3          2             458551 READ WRITE ONLINE  /u01/oracle/oradata/XFF/sysaux01.dbf
         4          4             458567 READ ONLY  ONLINE  /u01/oracle/oradata/XFF/users01.dbf
         5          4             458567 READ ONLY  ONLINE  /u01/oracle/oradata/XFF/users02.dbf
SQL> select file#,status, CHECKPOINT_CHANGE# from v$datafile_header;
     FILE# STATUS  CHECKPOINT_CHANGE#
---------- ------- ------------------
         1 ONLINE              458551
         2 ONLINE              458551
         3 ONLINE              458551
         4 ONLINE              458567
         5 ONLINE              458567
SQL> alter system checkpoint;
System altered.
SQL>  select file#,ts#,CHECKPOINT_CHANGE#,enabled,status,name from v$datafile;
     FILE#        TS# CHECKPOINT_CHANGE# ENABLED    STATUS  NAME
---------- ---------- ------------------ ---------- ------- --------------------------------------------------
         1          0             458581 READ WRITE SYSTEM  /u01/oracle/oradata/XFF/system01.dbf
         2          1             458581 READ WRITE ONLINE  /u01/oracle/oradata/XFF/undotbs01.dbf
         3          2             458581 READ WRITE ONLINE  /u01/oracle/oradata/XFF/sysaux01.dbf
         4          4             458567 READ ONLY  ONLINE  /u01/oracle/oradata/XFF/users01.dbf
         5          4             458567 READ ONLY  ONLINE  /u01/oracle/oradata/XFF/users02.dbf
SQL> select file#,status, CHECKPOINT_CHANGE# from v$datafile_header;
     FILE# STATUS  CHECKPOINT_CHANGE#
---------- ------- ------------------
         1 ONLINE              458581
         2 ONLINE              458581
         3 ONLINE              458581
         4 ONLINE              458567
         5 ONLINE              458567
SQL> alter tablespace users read write;
Tablespace altered.
SQL> select file#,ts#,CHECKPOINT_CHANGE#,enabled,status,name from v$datafile;
     FILE#        TS# CHECKPOINT_CHANGE# ENABLED    STATUS  NAME
---------- ---------- ------------------ ---------- ------- --------------------------------------------------
         1          0             458581 READ WRITE SYSTEM  /u01/oracle/oradata/XFF/system01.dbf
         2          1             458581 READ WRITE ONLINE  /u01/oracle/oradata/XFF/undotbs01.dbf
         3          2             458581 READ WRITE ONLINE  /u01/oracle/oradata/XFF/sysaux01.dbf
         4          4             458635 READ WRITE ONLINE  /u01/oracle/oradata/XFF/users01.dbf
         5          4             458635 READ WRITE ONLINE  /u01/oracle/oradata/XFF/users02.dbf
SQL> select file#,status, CHECKPOINT_CHANGE# from v$datafile_header;
     FILE# STATUS  CHECKPOINT_CHANGE#
---------- ------- ------------------
         1 ONLINE              458581
         2 ONLINE              458581
         3 ONLINE              458581
         4 ONLINE              458635
         5 ONLINE              458635
SQL> alter system checkpoint;
System altered.
SQL>  select file#,ts#,CHECKPOINT_CHANGE#,enabled,status,name from v$datafile;
     FILE#        TS# CHECKPOINT_CHANGE# ENABLED    STATUS  NAME
---------- ---------- ------------------ ---------- ------- --------------------------------------------------
         1          0             458649 READ WRITE SYSTEM  /u01/oracle/oradata/XFF/system01.dbf
         2          1             458649 READ WRITE ONLINE  /u01/oracle/oradata/XFF/undotbs01.dbf
         3          2             458649 READ WRITE ONLINE  /u01/oracle/oradata/XFF/sysaux01.dbf
         4          4             458649 READ WRITE ONLINE  /u01/oracle/oradata/XFF/users01.dbf
         5          4             458649 READ WRITE ONLINE  /u01/oracle/oradata/XFF/users02.dbf
SQL> select file#,status, CHECKPOINT_CHANGE# from v$datafile_header;
     FILE# STATUS  CHECKPOINT_CHANGE#
---------- ------- ------------------
         1 ONLINE              458649
         2 ONLINE              458649
         3 ONLINE              458649
         4 ONLINE              458649
         5 ONLINE              458649

以上部分证明：
1.tablespace read only 对应的v$datafile.enabled为READ ONLY
2.tablespace read only与tablespace read write之间的转换也不会触发database checkpoint

补充说明
官方文档给出来的v$datafile.enabled有以下几种
DISABLED – No SQL access allowed
READ ONLY – No SQL updates allowed
READ WRITE – Full access allowed
UNKNOWN – should not occur unless the control file is corrupted
但是对于UNKNOWN我通过模拟重建控制文件,缺少数据文件(为READ WRITE),通过在线删除数据文件(为READ WRITE),都不能出现UNKNOWN状态,如果知道的朋友请告知我.

kill oracle session相关描述

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标题：kill oracle session相关描述

近期看到不少朋友都对kill session相关的参数不太熟悉,下面是摘自Oracle® Database SQL Reference

语法参考

DISCONNECT SESSION Clause

Use the DISCONNECT SESSION clause to disconnect the current session by destroying the dedicated server process
(or virtual circuit if the connection was made by way of a Shared Sever).
To use this clause, your instance must have the database open.
You must identify the session with both of the following values from the V$SESSION view:
•	For integer1, specify the value of the SID column.
•	For integer2, specify the value of the SERIAL# column.
If system parameters are appropriately configured, then application failover will take effect.
•	The POST_TRANSACTION setting allows ongoing transactions to complete before the session is disconnected.
        If the session has no ongoing transactions, then this clause has the same effect described for as KILL SESSION.
•	The IMMEDIATE setting disconnects the session and recovers the entire session state immediately,
        without waiting for ongoing transactions to complete.
o	If you also specify POST_TRANSACTION and the session has ongoing transactions, then the IMMEDIATE keyword is ignored.
o	If you do not specify POST_TRANSACTION, or you specify POST_TRANSACTION but the session has no ongoing transactions,
        then this clause has the same effect as described for KILL SESSION IMMEDIATE.

KILL SESSION Clause

The KILL SESSION clause lets you mark a session as terminated, roll back ongoing transactions,
release all session locks, and partially recover session resources.
To use this clause, your instance must have the database open.
Your session and the session to be terminated must be on the same instance unless you specify integer3.
You must identify the session with the following values from the V$SESSION view:
•	For integer1, specify the value of the SID column.
•	For integer2, specify the value of the SERIAL# column.
•	For the optional integer3, specify the ID of the instance where the target session to be killed exists.
        You can find the instance ID by querying the GV$ tables.
If the session is performing some activity that must be completed,
such as waiting for a reply from a remote database or rolling back a transaction,
then Oracle Database waits for this activity to complete, marks the session as terminated,
and then returns control to you.
If the waiting lasts a minute, then Oracle Database marks the session to be terminated
and returns control to you with a message that the session is marked to be terminated.
The PMON background process then marks the session as terminated when the activity is complete.
Whether or not the session has an ongoing transaction, Oracle Database does not recover
the entire session state until the session user issues a request to the session
and receives a message that the session has been terminated.

IMMEDIATE Specify IMMEDIATE to instruct Oracle Database to roll back ongoing transactions,
release all session locks, recover the entire session state, and return control to you immediately.

执行案例

--Oracle 级别kill
SQL> ALTER SYSTEM KILL SESSION 'sid,serial#';
SQL> ALTER SYSTEM KILL SESSION 'sid,serial#,@inst_id';
SQL> ALTER SYSTEM KILL SESSION 'sid,serial#' IMMEDIATE;
SQL> ALTER SYSTEM DISCONNECT SESSION 'sid,serial#' POST_TRANSACTION;
SQL> ALTER SYSTEM DISCONNECT SESSION 'sid,serial#' IMMEDIATE;
--Linux/Unix kill
kill -9 spid
--Windows kill
orakill ORACLE_SID spid

因非常规操作导致删除表空间提示ORA-01561解决办法

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标题：因非常规操作导致删除表空间提示ORA-01561解决办法

今天测试手工通过bbed修改undo$中回滚段状态(从status$=5修改为1)[NEEDS RECOVERY 修改为 DELETE],然后尝试删除表空间,发现不能删除
删除表空间提示ORA-01561

SQL> drop tablespace undotbs;
drop tablespace undotbs
*
ERROR at line 1:
ORA-01561: failed to remove all objects in the tablespace specified
SQL> drop tablespace undotbs including contents;
drop tablespace undotbs including contents
*
ERROR at line 1:
ORA-01561: failed to remove all objects in the tablespace specified

查询相关信息

SQL> select ts#,name from v$tablespace;
       TS# NAME
---------- ------------------------------
         0 SYSTEM
         1 SYSAUX
         4 USERS
         6 UNDOTBS
         3 TEMP
SQL> select name,ts#,status$ from undo$;
NAME                                  TS#    STATUS$
------------------------------ ---------- ----------
SYSTEM                                  0          3
_SYSSMU1_3138885392$                    2          1
_SYSSMU2_4228238222$                    2          1
_SYSSMU3_2210742642$                    2          1
_SYSSMU4_1455318006$                    2          1
_SYSSMU5_3787622316$                    2          1
_SYSSMU6_2460248069$                    2          1
_SYSSMU7_1924883037$                    2          1
_SYSSMU8_1909280886$                    2          1
_SYSSMU9_3593450615$                    2          1
_SYSSMU10_2490256178$                   2          1
NAME                                  TS#    STATUS$
------------------------------ ---------- ----------
_SYSSMU11_253524401$                    6          1
_SYSSMU12_842775869$                    6          1
_SYSSMU13_2794767139$                   6          1
_SYSSMU14_2067649841$                   6          1
_SYSSMU15_3270221471$                   6          1
_SYSSMU16_4094338609$                   6          1
_SYSSMU17_709661646$                    6          1
_SYSSMU18_699588262$                    6          1
_SYSSMU19_718640828$                    6          1
_SYSSMU20_3516920665$                   6          1
_SYSSMU21_793796797$                    6          1
NAME                                  TS#    STATUS$
------------------------------ ---------- ----------
_SYSSMU22_3988785920$                   6          1
_SYSSMU23_1828333848$                   6          1
_SYSSMU24_1223218862$                   6          1
_SYSSMU25_2939844199$                   6          1
_SYSSMU26_1317300205$                   6          1
_SYSSMU27_1654033223$                   6          1
_SYSSMU28_3748619502$                   6          1
_SYSSMU29_1868765904$                   6          1
_SYSSMU30_3379578723$                   6          1
31 rows selected.
SQL> select segment_name,status from dba_rollback_segs;
SEGMENT_NAME                   STATUS
------------------------------ ----------------
SYSTEM                         ONLINE

通过这里可以看出,通过bbed的修改,除system回滚段外,其他均已经被标志为delete状态,对于这样的情况,很本能的怀疑是extent或者segment未被清理掉导致

查询EXTENT和SEGMENT

SQL> select SEGMENT_NAME from dba_extents where TABLESPACE_NAME='UNDOTBS';
no rows selected
SQL> select segment_name from dba_segments where  TABLESPACE_NAME='UNDOTBS';
no rows selected
SQL> select count(*) from seg$ where ts#=6;
  COUNT(*)
----------
        10
SQL> select count(*) from seg$ where ts#=2;
  COUNT(*)
----------
         0
SQL> select file#,type# from  seg$ where ts#=6;
     FILE#      TYPE#
---------- ----------
         3         10
         3         10
         3         10
         3         10
         3         10
         3         10
         3         10
         3         10
         3         10
         3         10
10 rows selected.

通过查询我们发现SEG$中含有10条记录,而通过dbms_metadata.get_ddl分析DBA_SEGMENTS是的,得出type为10恰好是TYPE2 UNDO信息.

解决办法
删除掉这些因为手工修改undo$信息导致遗留下来的后遗症对象

SQL> delete from seg$ where ts#=6;
10 rows deleted.
SQL> commit;
Commit complete.
SQL> drop tablespace undotbs ;
Tablespace dropped.

这样的直接修改基表的做法,在一般的情况下非常不建议使用,可能带来系统不稳定.但是在数据库异常处理过程中,可能将成为一个法宝

ALERT_QUE表重建方法

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标题：ALERT_QUE表重建方法

最近关注了下网络上,出现了很多AQ$_ALERT_QT_N的index SYS_IOT_TOP_NNNN坏块引起的数据库异常(主要是SYSAUX表空间),因为他们是IOT表和主键的关系,不能简单的rebuild.查询了一些资料,得到一些信息

ALERT_QUE表用途
The ALERT_QUE is used by the Grid Control and DB Control Management Agents to monitor server-generated alerts

ALERT_QUE表重建方法

--方法1
SQL> connect / as sysdba
SQL>alter system enable restricted session;
To drop server alert schema.
SQL>@$ORACLE_HOME/rdbms/admin/catnoalr.sql
To re-create tables, sequence, type and queue for server alert
SQL>@$ORACLE_HOME/rdbms/admin/dbmsslrt.sql
SQL>@$ORACLE_HOME/rdbms/admin/catalrt.sql
To recompile the invalid objects
SQL>@$ORACLE_HOME/rdbms/admin/utlrp.sql
SQL> alter system disable restricted session;
--方法2
SQL> connect / as sysdba
SQL>alter system enable restricted session;
To drop server alert schema.
SQL>@$ORACLE_HOME/rdbms/admin/catnoalr.sql
Rerun catproc.sql
SQL>@$ORACLE_HOME/rdbms/admin/catproc.sql
SQL> alter system disable restricted session;

补充说明

By running the script up, the queue tables will be recreated and the messages
in the queue will be lost.
For 11g you can use catmwin.sql which has the steps to recreate the ALERT_QT.
Alternatively, for 11g you can use the catproc.sql to recreate.
If this option may leave DBSNMP.MGMT_BSLN_INTERNAL invalid.
To validate the same run catsnmp.sql [NOTE:603289.1]

Oracle 11g增加列,并带默认值的新特性

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标题：Oracle 11g增加列,并带默认值的新特性

在11g以前,如果要在一个大表中增加一列,并设置默认值,那将是一个非常悲剧的事情.有些时候不得不选择在线重定义功能来实现该需求.而在11g中增加新列并设置默认值,只是简单的修改数据字典来实现该功能,大大提供效率
10g加列(默认值)

SQL> select * from v$version;
BANNER
----------------------------------------------------------------
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Prod
PL/SQL Release 10.2.0.1.0 - Production
CORE    10.2.0.1.0      Production
TNS for Linux: Version 10.2.0.1.0 - Production
NLSRTL Version 10.2.0.1.0 - Production
SQL> create table t_xifenfei
  2  as select object_id,object_name from dba_objects;
Table created.
SQL> select count(*) from t_xifenfei;
  COUNT(*)
----------
     49827
SQL> desc t_xifenfei
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 OBJECT_ID                                          NUMBER
 OBJECT_NAME                                        VARCHAR2(128)
SQL> set timing on
SQL> alter table t_xifenfei add c_xff varchar2(100) default 'www.xifenfei.com' not null;
Table altered.
Elapsed: 00:00:06.13
--使用了6秒钟
SQL> select   rowid,
  2   dbms_rowid.rowid_relative_fno(rowid)rel_fno,
  3   dbms_rowid.rowid_block_number(rowid)blockno,
  4   dbms_rowid.rowid_row_number(rowid) rowno
  5  from t_xifenfei where object_name='OBJ$';
ROWID                 REL_FNO    BLOCKNO      ROWNO
------------------ ---------- ---------- ----------
AAAMwJAAEAAAAB8AAr          4        124         43
SQL> alter system dump datafile 4 block 124;
System altered.
Elapsed: 00:00:00.08

11g增加列(默认值)

SQL> select * from v$version;
BANNER
-----------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - Production
PL/SQL Release 11.2.0.3.0 - Production
CORE    11.2.0.3.0      Production
TNS for Linux: Version 11.2.0.3.0 - Production
NLSRTL Version 11.2.0.3.0 - Production
SQL> create table t_xifenfei
  2  as select object_id,object_name from dba_objects;
Table created.
SQL> select count(*) from t_xifenfei;
  COUNT(*)
----------
     74605
SQL> select   rowid,
  2   dbms_rowid.rowid_relative_fno(rowid)rel_fno,
  3   dbms_rowid.rowid_block_number(rowid)blockno,
  4   dbms_rowid.rowid_row_number(rowid) rowno
  5  from t_xifenfei where object_name='OBJ$';
ROWID                 REL_FNO    BLOCKNO      ROWNO
------------------ ---------- ---------- ----------
AAASpRAAEAAAACrAAu          4        171         46
SQL> alter system dump datafile 4 block 171;
System altered.
SQL> set timing on
SQL> alter table t_xifenfei add c_xff varchar2(100) default 'www.xifenfei.com' not null;
Table altered.
Elapsed: 00:00:00.19
--只是使用了0.19秒
SQL> select   rowid,
  2   dbms_rowid.rowid_relative_fno(rowid)rel_fno,
  3   dbms_rowid.rowid_block_number(rowid)blockno,
  4   dbms_rowid.rowid_row_number(rowid) rowno
  5  from t_xifenfei where object_name='OBJ$';
ROWID                 REL_FNO    BLOCKNO      ROWNO
------------------ ---------- ---------- ----------
AAASpRAAEAAAACrAAu          4        171         46
Elapsed: 00:00:00.04
SQL> alter system dump datafile 4 block 171;
System altered.

通过10g和11g的增加相同列和默认值的对比可以发现,11g的速度要比10g快很多很多,下面我们通过上面dump出来相关的数据块来分析原因
dump分析
11g增加列之前dump

tab 0, row 0, @0x1f74
tl: 12 fb: --H-FL-- lb: 0x0  cc: 2
col  0: [ 2]  c1 15
col  1: [ 5]  49 43 4f 4c 24
tab 0, row 1, @0x1f66
tl: 14 fb: --H-FL-- lb: 0x0  cc: 2
col  0: [ 2]  c1 2f
col  1: [ 7]  49 5f 55 53 45 52 31
tab 0, row 2, @0x1f5b
tl: 11 fb: --H-FL-- lb: 0x0  cc: 2
col  0: [ 2]  c1 1d
col  1: [ 4]  43 4f 4e 24

11g增加列之后dump

tab 0, row 0, @0x1f74
tl: 12 fb: --H-FL-- lb: 0x0  cc: 2
col  0: [ 2]  c1 15
col  1: [ 5]  49 43 4f 4c 24
tab 0, row 1, @0x1f66
tl: 14 fb: --H-FL-- lb: 0x0  cc: 2
col  0: [ 2]  c1 2f
col  1: [ 7]  49 5f 55 53 45 52 31
tab 0, row 2, @0x1f5b
tl: 11 fb: --H-FL-- lb: 0x0  cc: 2
col  0: [ 2]  c1 1d
col  1: [ 4]  43 4f 4e 24
tab 0, row 3, @0x1f4f
tl: 12 fb: --H-FL-- lb: 0x0  cc: 2
col  0: [ 2]  c1 10
col  1: [ 5]  55 4e 44 4f 24

10g增加列之后dump
因为10g在没有增加列之前的dump和11g未增加列之前类似,所以未dump出来

tab 0, row 0, @0x1f63
tl: 29 fb: --H-FL-- lb: 0x2  cc: 3
col  0: [ 2]  c1 15
col  1: [ 5]  49 43 4f 4c 24
col  2: [16]  77 77 77 2e 78 69 66 65 6e 66 65 69 2e 63 6f 6d
tab 0, row 1, @0x1f44
tl: 31 fb: --H-FL-- lb: 0x2  cc: 3
col  0: [ 2]  c1 2d
col  1: [ 7]  49 5f 55 53 45 52 31
col  2: [16]  77 77 77 2e 78 69 66 65 6e 66 65 69 2e 63 6f 6d
tab 0, row 2, @0x1f28
tl: 28 fb: --H-FL-- lb: 0x2  cc: 3
col  0: [ 2]  c1 1d
col  1: [ 4]  43 4f 4e 24
col  2: [16]  77 77 77 2e 78 69 66 65 6e 66 65 69 2e 63 6f 6d
tab 0, row 3, @0x1f0b
tl: 29 fb: --H-FL-- lb: 0x2  cc: 3
col  0: [ 2]  c1 10
col  1: [ 5]  55 4e 44 4f 24
col  2: [16]  77 77 77 2e 78 69 66 65 6e 66 65 69 2e 63 6f 6d

对比发现11g在增加列之后,以前的数据dump出来的内容未有任何改变.也就是说:在10g中,我们增加一个列和默认值,会自动的增加到真实的数据中,而在11g中增加列和默认值并未真的加到11g的表中已经存在的数据中.
11g中插入新数据dump测试

SQL>  insert into chf.t_xifenfei(object_id,object_name)
  2  select object_id,object_name FROM DBA_OBJECTS;
74605 rows created.
SQL> commit;
Commit complete.
SQL> ALTER SYSTEM FLUSH BUFFER_CACHE;
System altered.
SQL> /
System altered.
--建议刷新
SQL>
SQL>
SQL> select   rowid,
  2   dbms_rowid.rowid_relative_fno(rowid)rel_fno,
  3   dbms_rowid.rowid_block_number(rowid)blockno,
  4   dbms_rowid.rowid_row_number(rowid) rowno
  5  from chf.t_xifenfei where object_name='OBJ$';
ROWID                 REL_FNO    BLOCKNO      ROWNO
------------------ ---------- ---------- ----------
AAASpRAAEAAAACrAAu          4        171         46
AAASpRAAEAAAB5TAAu          4       7763         46
SQL> ALTER SYSTEM DUMP DATAFILE 4 BLOCK 7763;
System altered.
--dump内容
tab 0, row 0, @0x4e3
tl: 29 fb: --H-FL-- lb: 0x1  cc: 3
col  0: [ 2]  c1 15
col  1: [ 5]  49 43 4f 4c 24
col  2: [16]  77 77 77 2e 78 69 66 65 6e 66 65 69 2e 63 6f 6d
tab 0, row 1, @0x500
tl: 31 fb: --H-FL-- lb: 0x1  cc: 3
col  0: [ 2]  c1 2f
col  1: [ 7]  49 5f 55 53 45 52 31
col  2: [16]  77 77 77 2e 78 69 66 65 6e 66 65 69 2e 63 6f 6d
tab 0, row 2, @0x51f
tl: 28 fb: --H-FL-- lb: 0x1  cc: 3
col  0: [ 2]  c1 1d
col  1: [ 4]  43 4f 4e 24
col  2: [16]  77 77 77 2e 78 69 66 65 6e 66 65 69 2e 63 6f 6d
tab 0, row 3, @0x53b
tl: 29 fb: --H-FL-- lb: 0x1  cc: 3
col  0: [ 2]  c1 10
col  1: [ 5]  55 4e 44 4f 24
col  2: [16]  77 77 77 2e 78 69 66 65 6e 66 65 69 2e 63 6f 6d

通过这里看看出:在11g中后续插入的数据,默认值也插入到数据文件中

Oracle 11G的DDL_LOCK_TIMEOUT参数

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

标题：Oracle 11G的DDL_LOCK_TIMEOUT参数

今天kaums给客户做培训11g新特性,发现还真的有不少挺好的新东西,但是以前没有怎么去关注的他们,在后续的几篇中,陆续整理处理.
DDL_LOCK_TIMEOUT specifies a time limit for how long DDL statements will wait in a DML lock queue. The default value of zero indicates a status of NOWAIT. The maximum value of 1,000,000 seconds will result in the DDL statement waiting forever to acquire a DML lock.
If a lock is not acquired before the timeout period expires, then an error is returned.
数据库ddl_lock_timeout参数

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> show parameter ddl_lock_timeout;
NAME                                 TYPE       VALUE
------------------------------------ ---------- --------------
ddl_lock_timeout                     integer    0

ddl_lock_timeout默认值测试(同以前版本)

--会话1
SQL> set time on
10:27:57 SQL> create table t_xifenfei as
10:28:05   2  select * from dba_users;
Table created.
Elapsed: 00:00:00.08
10:28:17 SQL> delete from t_xifenfei where username='CHF';
1 row deleted.
--会话2
SQL> set timing on
SQL> ALTER TABLE T_XIFENFEI DROP COLUMN AUTHENTICATION_TYPE;
ALTER TABLE T_XIFENFEI DROP COLUMN AUTHENTICATION_TYPE
            *
ERROR at line 1:
ORA-00054: resource busy and acquire with NOWAIT specified or timeout expired
Elapsed: 00:00:00.01

设置ddl_lock_timeout超时测试

--会话1
10:28:17 SQL> delete from t_xifenfei where username='CHF';
1 row deleted.
--会话2
SQL>  ALTER SESSION SET ddl_lock_timeout=10;
Session altered.
Elapsed: 00:00:00.00
SQL> ALTER TABLE T_XIFENFEI DROP COLUMN AUTHENTICATION_TYPE;
ALTER TABLE T_XIFENFEI DROP COLUMN AUTHENTICATION_TYPE
            *
ERROR at line 1:
ORA-00054: resource busy and acquire with NOWAIT specified or timeout expired
Elapsed: 00:00:10.01

设置ddl_lock_timeout未超时测试

--会话2
SQL> ALTER SESSION SET ddl_lock_timeout=30;
Session altered.
Elapsed: 00:00:00.00
--会话1
10:30:00 SQL> COMMIT;
Commit complete.
Elapsed: 00:00:00.00
--会话2
SQL> ALTER TABLE T_XIFENFEI DROP COLUMN AUTHENTICATION_TYPE;
Table altered.
Elapsed: 00:00:07.91

在以前的版本中ddl操作是nowait等待,通过实验可以发现ddl_lock_timeout可以在一定程度上解决因为我们不清楚这个表是否有dml操作而导致ddl操作不能进行的情况,从一定程度上减少了自己去尝试ddl操作,或者查询相关视图然后找出相关会话,然后kill掉对应数据的情况,可以说是在修改表结构的时候一个很不错的新特性.

gv$视图不能查询所有节点信息

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

标题：gv$视图不能查询所有节点信息

今天遇到诡异的事情,AIX 5.3 ORACLE 9I RAC的gv$视图只能查询到本地的记录,而不是所有节点.但是所有节点均运行正常,除gv$视图之外未发现其他异常.
异常时节点1信息

SQL> show parameter clu;
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
cluster_database                     boolean     TRUE
cluster_database_instances           integer     2
cluster_interconnects                string      192.168.6.24
SQL> select * from v$version;
BANNER
----------------------------------------------------------------
Oracle9i Enterprise Edition Release 9.2.0.8.0 - 64bit Production
PL/SQL Release 9.2.0.8.0 - Production
CORE    9.2.0.8.0       Production
TNS for IBM/AIX RISC System/6000: Version 9.2.0.8.0 - Production
NLSRTL Version 9.2.0.8.0 - Production
SQL> col host_name for a10
SQL> select inst_id,HOST_NAME,STATUS from gv$instance;
   INST_ID HOST_NAME  STATUS
---------- ---------- ------------
         1 zwq_crm1   OPEN
SQL> show parameter par;
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
fast_start_parallel_rollback         string      LOW
log_parallelism                      integer     1
parallel_adaptive_multi_user         boolean     FALSE
parallel_automatic_tuning            boolean     FALSE
parallel_execution_message_size      integer     2152
parallel_instance_group              string
parallel_max_servers                 integer     5
parallel_min_percent                 integer     0
parallel_min_servers                 integer     0
parallel_server                      boolean     TRUE
parallel_server_instances            integer     2
parallel_threads_per_cpu             integer     2
partition_view_enabled               boolean     FALSE
recovery_parallelism                 integer     0
SQL> !ps -ef|grep p0
  oracrm 1929258       1   0 09:49:19      -  0:01 ora_p005_crm1
  oracrm  745844       1   0   Jun 26      -  0:20 ora_p004_crm1
  oraeye 2421272 3948648   0 21:53:49  pts/0  0:00 grep p0
  oracrm 3060406       1   0   Jun 26      -  0:20 ora_p002_crm1
  oracrm 3170868       1   0   Jun 20      -  2:13 ora_p000_crm1
  oracrm  787414       1   0   Jun 26      -  0:20 ora_p001_crm1
  oracrm 2552690       1   0   Jun 26      -  0:20 ora_p003_crm1

1.节点最大允许5个并发进程,现在已经启动并发进程到p005(6个)
2.gv$视图只能查询一个节点信息

异常时节点2信息
问题所有情况和1节点完全相似

SQL> col host_name for a10
SQL> select inst_id,HOST_NAME,STATUS from gv$instance;
   INST_ID HOST_NAME  STATUS
---------- ---------- ------------
         2 zwq_crm2   OPEN
SQL> show parameter par;
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
fast_start_parallel_rollback         string      LOW
log_parallelism                      integer     1
parallel_adaptive_multi_user         boolean     FALSE
parallel_automatic_tuning            boolean     FALSE
parallel_execution_message_size      integer     2152
parallel_instance_group              string
parallel_max_servers                 integer     5
parallel_min_percent                 integer     0
parallel_min_servers                 integer     0
parallel_server                      boolean     TRUE
parallel_server_instances            integer     2
parallel_threads_per_cpu             integer     2
partition_view_enabled               boolean     FALSE
recovery_parallelism                 integer     0
SQL> !ps -ef|grep p0
  oracrm 1867938       1   0 15:17:25      -  0:00 ora_p004_crm2
  oracrm 2633748       1   0 09:49:19      -  0:01 ora_p005_crm2
  oraeye 3059876 1007714   0 21:54:01  pts/0  0:00 grep p0
  oracrm  323884       1 120   Jun 20      - 10692:47 ora_p000_crm2
  oracrm 1839818       1   0 06:16:32      -  0:00 ora_p003_crm2
  oracrm  459660       1 107   Jun 26      - 1857:00 ora_p001_crm2
  oracrm 2351894       1   0 16:52:52      -  0:00 ora_p002_crm2

在异常2节点上做10046

SQL> oradebug setmypid
Statement processed.
SQL> oradebug EVENT 10046 TRACE NAME CONTEXT FOREVER, LEVEL 4
Statement processed.
SQL> select * from gv$version;
   INST_ID BANNER
---------- ----------------------------------------------------------------
         2 Oracle9i Enterprise Edition Release 9.2.0.8.0 - 64bit Production
         2 PL/SQL Release 9.2.0.8.0 - Production
         2 CORE 9.2.0.8.0       Production
         2 TNS for IBM/AIX RISC System/6000: Version 9.2.0.8.0 - Production
         2 NLSRTL Version 9.2.0.8.0 - Production
SQL> oradebug EVENT 10046 trace name context off
Statement processed.
SQL> oradebug TRACEFILE_NAME
/oracle9/app/admin/crm/udump/crm2_ora_517066.trc

分析10046内容发现

PARSING IN CURSOR #1 len=24 dep=0 uid=0 oct=3 lid=0 tim=41759005850609 hv=775381991 ad='21195808'
select * from gv$version
END OF STMT
PARSE #1:c=20000,e=33894,p=1,cr=59,cu=3,mis=1,r=0,dep=0,og=4,tim=41759005850607
BINDS #1:
kxfpg1srv
        could not start P006, inst 1
kxfpg1srv
        could not start local P006
EXEC #1:c=0,e=3540,p=0,cr=0,cu=0,mis=0,r=0,dep=0,og=4,tim=41759005854254
FETCH #1:c=0,e=28,p=0,cr=0,cu=0,mis=0,r=1,dep=0,og=4,tim=41759005854347
FETCH #1:c=0,e=23,p=0,cr=0,cu=0,mis=0,r=4,dep=0,og=4,tim=41759005854678
STAT #1 id=1 cnt=5 pid=0 pos=1 obj=0 op='VIEW  '
STAT #1 id=2 cnt=5 pid=1 pos=1 obj=304 op='FIXED TABLE FULL X$VERSION '

通过这里观察10046可以看到:在2节点上查询gv$instance,需要通过使用并发进程去访问1节点,但是因为1节点的parallel_max_servers为5,而当前的并发进程已经达到最大数目,从而使得想在节点1上启动并发失败,进入使得gv$视图只能查询出来本节点数据

gv$视图异常解决方法

--重启两个节点,查询正常
SQL> col host_name for a10
SQL> select inst_id,HOST_NAME,STATUS from gv$instance;
   INST_ID HOST_NAME  STATUS
---------- ---------- ------------
         1 zwq_crm1   OPEN
         2 zwq_crm2   OPEN

针对这个问题,很可能是oracle bug(因为是9i版本,我无法深究),或者是并发进程僵死所致,当时有一个想法,kill 掉数据库并发进程,因客户不同意(采用稳妥重启方案),未能通过尝试验证我的猜想.

对gv$视图正常做10046

SQL> oradebug setmypid
Statement processed.
SQL> oradebug EVENT 10046 TRACE NAME CONTEXT FOREVER, LEVEL 12
Statement processed.
SQL> select * from gv$version;
   INST_ID BANNER
---------- ----------------------------------------------------------------
         1 Oracle9i Enterprise Edition Release 9.2.0.8.0 - 64bit Production
         1 PL/SQL Release 9.2.0.8.0 - Production
         1 CORE 9.2.0.8.0       Production
         1 TNS for IBM/AIX RISC System/6000: Version 9.2.0.8.0 - Production
         1 NLSRTL Version 9.2.0.8.0 - Production
         2 Oracle9i Enterprise Edition Release 9.2.0.8.0 - 64bit Production
         2 PL/SQL Release 9.2.0.8.0 - Production
         2 CORE 9.2.0.8.0       Production
         2 TNS for IBM/AIX RISC System/6000: Version 9.2.0.8.0 - Production
         2 NLSRTL Version 9.2.0.8.0 - Production
10 rows selected.
SQL> oradebug EVENT 10046 trace name context off
Statement processed.
SQL> oradebug TRACEFILE_NAME
/oracle9/app/admin/crm/udump/crm1_ora_1708916.trc

分析10046内容

PARSING IN CURSOR #1 len=24 dep=0 uid=0 oct=3 lid=0 tim=41752681925071 hv=775381991 ad='92ef64f0'
select * from gv$version
END OF STMT
PARSE #1:c=0,e=6770,p=0,cr=12,cu=3,mis=1,r=0,dep=0,og=4,tim=41752681925070
BINDS #1:
WAIT #1: nam='PX Deq: reap credit' ela= 21 p1=0 p2=0 p3=0
WAIT #1: nam='PX Deq: Join ACK' ela= 237 p1=268500992 p2=1 p3=504403208016510312
WAIT #1: nam='PX Deq: reap credit' ela= 4 p1=0 p2=0 p3=0
WAIT #1: nam='PX Deq: Join ACK' ela= 64 p1=268500992 p2=2 p3=504403208016510312
WAIT #1: nam='PX Deq: reap credit' ela= 3 p1=0 p2=0 p3=0
WAIT #1: nam='PX Deq: reap credit' ela= 3 p1=0 p2=0 p3=0
WAIT #1: nam='PX Deq: Join ACK' ela= 46 p1=268566528 p2=1 p3=504403208016502096
WAIT #1: nam='PX Deq: reap credit' ela= 4 p1=0 p2=0 p3=0
WAIT #1: nam='PX Deq: Join ACK' ela= 855 p1=268566528 p2=2 p3=504403208016502096
WAIT #1: nam='PX Deq: reap credit' ela= 4 p1=0 p2=0 p3=0
WAIT #1: nam='PX Deq: reap credit' ela= 3 p1=0 p2=0 p3=0
WAIT #1: nam='PX Deq Credit: send blkd' ela= 188 p1=268566528 p2=1 p3=504403208016502096
WAIT #1: nam='PX Deq: reap credit' ela= 1 p1=0 p2=0 p3=0
WAIT #1: nam='PX Deq: reap credit' ela= 3 p1=0 p2=0 p3=0
WAIT #1: nam='PX Deq: reap credit' ela= 3 p1=0 p2=0 p3=0
WAIT #1: nam='PX Deq: Parse Reply' ela= 406 p1=200 p2=1 p3=0
WAIT #1: nam='PX Deq: reap credit' ela= 3 p1=0 p2=0 p3=0
WAIT #1: nam='PX Deq: Parse Reply' ela= 7442 p1=200 p2=2 p3=0
WAIT #1: nam='PX Deq: reap credit' ela= 4 p1=0 p2=0 p3=0
WAIT #1: nam='PX Deq: reap credit' ela= 3 p1=0 p2=0 p3=0
WAIT #1: nam='PX Deq: Parse Reply' ela= 1664 p1=200 p2=1 p3=0
WAIT #1: nam='PX Deq: reap credit' ela= 3 p1=0 p2=0 p3=0
EXEC #1:c=0,e=11572,p=0,cr=0,cu=0,mis=0,r=0,dep=0,og=4,tim=41752681936727
WAIT #1: nam='SQL*Net message to client' ela= 1 p1=1650815232 p2=1 p3=0
WAIT #1: nam='PX Deq: reap credit' ela= 3 p1=0 p2=0 p3=0
WAIT #1: nam='PX Deq: Execute Reply' ela= 166 p1=200 p2=1 p3=0
WAIT #1: nam='PX Deq: reap credit' ela= 3 p1=0 p2=0 p3=0
WAIT #1: nam='PX Deq: Execute Reply' ela= 310 p1=200 p2=2 p3=0
WAIT #1: nam='PX Deq: reap credit' ela= 3 p1=0 p2=0 p3=0
FETCH #1:c=0,e=557,p=0,cr=0,cu=0,mis=0,r=1,dep=0,og=4,tim=41752681937320
WAIT #1: nam='SQL*Net message from client' ela= 223 p1=1650815232 p2=1 p3=0
WAIT #1: nam='SQL*Net message to client' ela= 1 p1=1650815232 p2=1 p3=0
WAIT #1: nam='PX Deq: reap credit' ela= 18 p1=0 p2=0 p3=0
WAIT #1: nam='PX Deq: reap credit' ela= 3 p1=0 p2=0 p3=0
WAIT #1: nam='DFS lock handle' ela= 263 p1=1128857605 p2=9 p3=5
WAIT #1: nam='DFS lock handle' ela= 254 p1=1128857605 p2=9 p3=1
WAIT #1: nam='DFS lock handle' ela= 263 p1=1128857605 p2=9 p3=3
WAIT #1: nam='DFS lock handle' ela= 73 p1=1128857605 p2=9 p3=2
WAIT #1: nam='DFS lock handle' ela= 363 p1=1128857605 p2=9 p3=2
WAIT #1: nam='PX Deq: reap credit' ela= 3 p1=0 p2=0 p3=0
WAIT #1: nam='PX Deq: reap credit' ela= 24 p1=0 p2=0 p3=0
WAIT #1: nam='PX Deq: Signal ACK' ela= 3 p1=0 p2=1 p3=0
WAIT #1: nam='PX Deq: reap credit' ela= 3 p1=0 p2=0 p3=0
WAIT #1: nam='PX Deq: Signal ACK' ela= 155 p1=10 p2=2 p3=0
WAIT #1: nam='PX Deq: reap credit' ela= 1 p1=0 p2=0 p3=0
FETCH #1:c=0,e=1735,p=0,cr=0,cu=0,mis=0,r=9,dep=0,og=4,tim=41752681939329
WAIT #1: nam='DFS lock handle' ela= 249 p1=1128857605 p2=9 p3=1
WAIT #1: nam='DFS lock handle' ela= 258 p1=1128857605 p2=9 p3=3
WAIT #1: nam='DFS lock handle' ela= 66 p1=1128857605 p2=9 p3=2
WAIT #1: nam='DFS lock handle' ela= 369 p1=1128857605 p2=9 p3=2
WAIT #1: nam='PX Deq: reap credit' ela= 3 p1=0 p2=0 p3=0
WAIT #1: nam='PX Deq: reap credit' ela= 19 p1=0 p2=0 p3=0
WAIT #1: nam='PX Deq: reap credit' ela= 1 p1=0 p2=0 p3=0
WAIT #1: nam='enqueue' ela= 201 p1=1347616774 p2=2 p3=0
WAIT #1: nam='enqueue' ela= 41 p1=1347616774 p2=2 p3=0
WAIT #1: nam='SQL*Net message from client' ela= 6981860 p1=1650815232 p2=1 p3=0
STAT #1 id=1 cnt=0 pid=0 pos=1 obj=0 op='VIEW  '
STAT #1 id=2 cnt=0 pid=1 pos=1 obj=304 op='FIXED TABLE FULL X$VERSION '

通过这里可以看出,rac在正常情况下gv$视图默认的查询就是并发方式进行

因未配置Hugepage会话数添增悲剧案例

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标题：因未配置Hugepage会话数添增悲剧案例

今天一朋友反馈他们的一个数据库hang住了,通过ssh也不能登录系统,他们没有办法重启系统解决问题,现在想让我帮忙找出问题原因
分析awr得出

询问朋友,他们的库一般session保持在200个左右,这次突然飙升到750以上,属于异常情况

分析监听日志

看到在截图的时间内,整体访问较频繁,某个ip访问异常频繁,通过这些信息,初步怀疑是用户的数据库内存使用完,导致系统数据库hang住.

查看系统日志

Jun 26 14:35:55 result01 kernel: [5613531.566617] Free swap  = 0kB
Jun 26 14:35:55 result01 kernel: [5613531.566618] Total swap = 2104504kB
Jun 26 14:35:55 result01 kernel: [5613531.566620] Free swap:            0kB
Jun 26 14:35:55 result01 kernel: [5613531.591073] 2359296 pages of RAM
Jun 26 14:35:55 result01 kernel: [5613531.591074] 318236 reserved pages
Jun 26 14:35:55 result01 kernel: [5613531.591075] 73353 pages shared
Jun 26 14:35:56 result01 kernel: [5613531.591076] 529 pages swap cached
Jun 26 14:35:56 result01 kernel: [5613531.591079] Out of Memory: Kill process 8904 (oracle) score 891 and children.
Jun 26 14:35:56 result01 kernel: [5613531.591201] Out of memory: Killed process 8904 (oracle).
Jun 26 14:35:56 result01 kernel: [5613531.592280] oracle invoked oom-killer: gfp_mask=0x201d2, order=0, oomkilladj=0

通过这个日志看出系统内存和交换分区都使用完,因为内存不够,系统开始kill掉部分oracle进程.通过这些确定是系统内存使用完导致hang住可以理解.

分析hang住原因
为什么session意外的从200添增到750的时候,系统内存被使用完

cat /proc/meminfo
MemTotal:      8164240 kB
SwapTotal:     2104504 kB
PageTables:      69732 kB
HugePages_Total:     0
HugePages_Free:      0
HugePages_Rsvd:      0
Hugepagesize:     2048 kB
sga_target=3674210304
pga_aggregate_target=1732247552

从这里得出几个信息:
1.数据库总内存8g,swap配置2g
2.数据库未使用Hugepage
3.数据库设置sga和pga信息

内存参数估算
数据库总计占用内存为:(3674210304+1732247552)/1024/1024=5156M(pga可能未使用完,也可能超过)
结合实际sga_target=3674210304,会话数.
保守估计下Oracle进程占用的系统内存3674210304/(4*1024)*1.5*750/1024/1024=960M
估算如果使用Hugepage Oracle进程占用系统内存为:3674210304/(2*1024*1024)*1.5*750/1024/1024=1.9M
通过这里分析Oracle总占用内存为:5156+960=6116M
通过保守计算留给系统的内存大概为:1.8G左右
因为系统的其他操作,最终导致该系统内存耗完,系统和数据库hang住

总结说明
这是一个实实在在因为linux中因为未配置Hugepage,因为用户突增,导致系统内存消耗光,从而使得系统和数据库hang住的例子.
这个库因为sga不是非常大,所以Oracle占用系统内存不是高到离谱,如果sga配置为32g,1000个session,那就会占用12g的系统内存
通过这些可以看出在linux中配置Hugepage的优点:Hugepage不光是为了减轻cpu的负担,还可以减少系统内存的消耗;在没有极端的情况下,建议linux的数据库系统配置Hugepage.

关于DBMS_SCHEDULER基础

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标题：关于DBMS_SCHEDULER基础

长期以来,一直对DBMS_SCHEDULER包比较模糊,今天抽一点时间,通过一点试验,理清自己的思路,分清楚各个函数大概作用.不至于在以后使用该包的时候一片空白.
1.通过DBMS_SCHEDULER.CREATE_JOB直接创建job

SQL> create table t_xifenfei (x_type varchar2(10),x_date date);
表已创建。
SQL> begin
  2  DBMS_SCHEDULER.create_job (
  3  job_name => 'f_create_job',
  4  job_type => 'PLSQL_BLOCK',
  5  job_action => '
  6   begin
  7   insert into t_xifenfei values(''job'',sysdate);
  8   commit;
  9   end;
 10  ',
 11  enabled => true,
 12  start_date => SYSTIMESTAMP,
 13  repeat_interval => 'SYSTIMESTAMP + 1/1440',
 14  comments => 'xifenfei_create_job');
 15  END;
 16  /
SQL> select x_type,to_char(x_date,'yyyy-mm-dd hh24:mi:ss') from t_xifenfei;
X_TYPE     TO_CHAR(X_DATE,'YYY
---------- -------------------
job        2012-06-19 19:52:11
job        2012-06-19 19:53:11
job        2012-06-19 19:54:11

这里的使用方法和dbms_jobs有几分类此,不过这个提供了加灵活的使用方法,比如可以执行匿名块,执行操作系统命令等

2.CREATE_JOB结合CREATE_PROGRAM

SQL>  create or replace procedure p_xifenfei(in_type in varchar2)
  2   is
  3   begin
  4   insert into t_xifenfei values(in_type,sysdate);
  5   commit;
  6   end;
  7   /
过程已创建。
SQL> begin
  2  DBMS_SCHEDULER.CREATE_PROGRAM(
  3  program_name => 'x_program',
  4  program_action => 'p_xifenfei',
  5  program_type => 'STORED_PROCEDURE',
  6  number_of_arguments => 1,
  7  comments => 'xifenfei_PROGRAM',
  8  enabled => false);
  9  end;
 10  /
PL/SQL 过程已成功完成。
SQL> begin
  2  DBMS_SCHEDULER.define_program_argument(
  3  program_name => 'x_program',
  4  argument_position => 1,
  5  argument_type => 'VARCHAR2',
  6  default_value => 'program');
  7  END;
  8  /
PL/SQL 过程已成功完成。
SQL>  exec DBMS_SCHEDULER.enable('x_program');
PL/SQL 过程已成功完成。
SQL> begin
  2  DBMS_SCHEDULER.create_job(
  3  job_name => 's_xifenfei_job',
  4  program_name => 'x_program',
  5  comments => 's_xifenfei_job',
  6  repeat_interval => 'SYSTIMESTAMP + 1/1440',
  7  auto_drop => false,
  8  enabled => true);
  9  end;
 10  /
PL/SQL 过程已成功完成。
SQL> select x_type,to_char(x_date,'yyyy-mm-dd hh24:mi:ss') from t_xifenfei;
X_TYPE     TO_CHAR(X_DATE,'YYY
---------- -------------------
job        2012-06-19 20:27:11
program    2012-06-19 20:27:09
program    2012-06-19 20:28:09
job        2012-06-19 20:28:11

这里可以看出来CREATE_PROGRAM是把CREATE_JOB中的部分参数给独立出来,使得更加灵活的控制,比如这里的使用从参数

3.CREATE_JOB结合CREATE_PROGRAM和CREATE_SCHEDULE

SQL> exec DBMS_SCHEDULER.drop_job('s_xifenfei_job');
PL/SQL 过程已成功完成。
SQL> truncate table t_xifenfei;
表被截断。
SQL> begin
  2  DBMS_SCHEDULER.create_schedule(
  3  repeat_interval => 'FREQ=MINUTELY;INTERVAL=1',
  4  start_date => sysdate,
  5  comments => 'xifenfei_sch',
  6  schedule_name => 'X_SCH');
  7  end;
  8  /
PL/SQL 过程已成功完成。
SQL> begin
  2  DBMS_SCHEDULER.create_job(
  3  job_name => 't_xifenfei_job',
  4  program_name => 'x_program',
  5  comments => 't_xifenfei_job',
  6  schedule_name => 'X_SCH',
  7  auto_drop => false,
  8  enabled => true);
  9  end;
 10  /
PL/SQL 过程已成功完成。
SQL> select x_type,to_char(x_date,'yyyy-mm-dd hh24:mi:ss') from t_xifenfei;
X_TYPE     TO_CHAR(X_DATE,'YYY
---------- -------------------
job        2012-06-19 20:39:11
job        2012-06-19 20:37:11
job        2012-06-19 20:38:11
program    2012-06-19 20:39:01
program    2012-06-19 20:40:01

CREATE_SCHEDULE是把执行计划部分从CREATE_JOB独立处理,使得控制力度更大,更加灵活

补充说明:
1.还可以通过创建JOB_CLASS更加灵活的控制资源的使用情况,必须通过修改JOB_CLASS中的resource_consumer_group实现资源控制,service对应到数据库的service可以实现rac中在哪个节点执行等等
2.使用DBMS_SCHEDULER.set_attribute来修改相关属相如:

EXEC DBMS_SCHEDULER.set_attribute('GATHER_STATS_JOB','JOB_CLASS', 'AUTO_TASKS_JOB_CLASS2');
exec dbms_scheduler.set_attribute('WEEKNIGHT_WINDOW','REPEAT_INTERVAL','freq=daily;
byday=MON,TUE,WED,THU,FRI;byhour=2;byminute=0;bysecond=0');

ORACLE在线切换undo表空间

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标题：ORACLE在线切换undo表空间

切换undo的一些步骤和基本原则

查看原undo相关参数
SHOW PARAMETER UNDO;
创建新undo空间
create undo tablespace undo_x datafile 'E:\ORACLE\ORADATA\XIFENFEI\undo_xifenfei.dbf' size 10M
autoextend on next 10M maxsize 30G;
查询历史undo是否还有事务(包含回滚事务)
SELECT a.tablespace_name,a.segment_name,b.ktuxesta,b.ktuxecfl,
b.ktuxeusn||'.'||b.ktuxeslt||'.'||b.ktuxesqn trans
FROM dba_rollback_segs a, x$ktuxe b
WHERE a.segment_id = b.ktuxeusn
AND a.tablespace_name = UPPER('&tsname')
AND b.ktuxesta <> 'INACTIVE';
--因为有undo_retention参数,所以不能简单的通过确定该sql无事务就可以删除原undo
切换undo表空间(无论是否有事务,均可以切换[最好是无事务时切换],但是不能直接删除原undo表空间)
alter system set undo_tablespace='undo_x';
alert日志现象,表明原undo还有事务
Sun Jun 17 20:10:45 2012
Successfully onlined Undo Tablespace 7.
[36428] **** active transactions found in undo Tablespace 2 - moved to Pending Switch-Out state.
[36428] active transactions found/affinity dissolution incompletein undo tablespace 2 during switch-out.
ALTER SYSTEM SET undo_tablespace='undo_xifenfei' SCOPE=BOTH;
Sun Jun 17 20:11:38 2012
[36312] **** active transactions found in undo Tablespace 2 - moved to Pending Switch-Out state.
Sun Jun 17 20:16:15 2012
[36312] **** active transactions found in undo Tablespace 2 - moved to Pending Switch-Out state.
--只能表明有事务,就算长时间未出现类似记录,不能证明一定可以删除原undo,因为undo_retention
查询回滚段情况(原undo表空间的回滚段全部offline,可以删除相关表空间)
select tablespace_name,segment_name,status from dba_rollback_segs;
离线原undo表空间
alter tablespace undotbs1 offline;
确定原undo回滚段全部offline,直接删除
drop tablespace undotbs1 including contents and datafiles;

切换undo表空间一句话：新建undo几乎是任何时候都可以执行切换undo表空间命令,如果要删除历史undo需要等到该undo空间所有回滚段全部offline.千万别在尚有回滚段处于online状态,强制删除数据文件.

分类目录归档：Oracle