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Oracle Recovery 04 - How to dump the control file

2018-06-02

Oracle Recovery 04 - How to dump the control file?

Database env

Linux: OEL7.3 x86-64

[oracle@databasevm001 ~]$ cat /etc/redhat-release 
Red Hat Enterprise Linux Server release 7.3 (Maipo)
[oracle@databasevm001 ~]$ uname -a
Linux databasevm001 4.1.12-61.1.28.el7uek.x86_64 #2 SMP Thu Feb 23 19:55:12 PST 2017 x86_64 x86_64 x86_64 GNU/Linux
[oracle@databasevm001 ~]$ 

SYS@orcl11g> select * from v$version;

Database: 11.2.0.4

BANNER
--------------------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - Production
PL/SQL Release 11.2.0.4.0 - Production
CORE    11.2.0.4.0      Production
TNS for Linux: Version 11.2.0.4.0 - Production
NLSRTL Version 11.2.0.4.0 - Production

SYS@orcl11g> 

Oracle Control file:dump

Use the following command to dumpe controlfile

alter session set events 'immediate trace name controlf level <n>';

Regarding the level:

level : level 1: Generic File Header 
Level 2: Level 1 + database information + database entry + check point progress records + Extended database entry 
level 3 or Higher< 9: level 2 + reuse record section 
level 10: Memory dump of all the control file logical blocks

Use the following command to find the path of trace file.

select * from v$diag_info where NAME='Default Trace File'; 

Example:

SYS@orcl11g> alter session set events 'immediate trace name controlf level 1';
Session altered.
SYS@orcl11g> select * from v$diag_info where NAME='Default Trace File'; 
INST_ID NAME                 VALUE
---------- -------------------- ----------------------------------------------------------------------
		1 Default Trace File   /u01/app/oracle/diag/rdbms/orcl11g/orcl11g/trace/orcl11g_ora_1310.trc
SYS@orcl11g> 

Output of dump controlfile

[oracle@databasevm001 ~]$ cat /u01/app/oracle/diag/rdbms/orcl11g/orcl11g/trace/orcl11g_ora_1310.trc
Trace file /u01/app/oracle/diag/rdbms/orcl11g/orcl11g/trace/orcl11g_ora_1310.trc
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
ORACLE_HOME = /u01/app/oracle/product/11.2.0.4/dbhome_1
System name:    Linux
Node name:      databasevm001
Release:        4.1.12-61.1.28.el7uek.x86_64
Version:        #2 SMP Thu Feb 23 19:55:12 PST 2017
Machine:        x86_64
Instance name: orcl11g
Redo thread mounted by this instance: 1
Oracle process number: 31
Unix process pid: 1310, image: oracle@databasevm001 (TNS V1-V3)

*** 2018-06-02 05:54:27.099
*** SESSION ID:(202.13) 2018-06-02 05:54:27.099
*** CLIENT ID:() 2018-06-02 05:54:27.099
*** SERVICE NAME:(SYS$USERS) 2018-06-02 05:54:27.099
*** MODULE NAME:(sqlplus@databasevm001 (TNS V1-V3)) 2018-06-02 05:54:27.099
*** ACTION NAME:() 2018-06-02 05:54:27.099

DUMP OF CONTROL FILES, Seq # 695 = 0x2b7
V10 STYLE FILE HEADER:
		Compatibility Vsn = 186647552=0xb200400
		Db ID=1068485233=0x3fafca71, Db Name='ORCL11G'
		Activation ID=0=0x0
		Control Seq=695=0x2b7, File size=614=0x266
		File Number=0, Blksiz=16384, File Type=1 CONTROL
*** END OF DUMP ***
[oracle@databasevm001 ~]$ 

Oracle Control file: file header

Fine some information with dump file.

DUMP OF CONTROL FILES, Seq # 695 = 0x2b7
V10 STYLE FILE HEADER:
		Compatibility Vsn = 186647552=0xb200400 #------------------------> the database version is 11.2.0.4
		Db ID=1068485233=0x3fafca71, Db Name='ORCL11G'
		Activation ID=0=0x0
		Control Seq=730=0x2da, File size=614=0x266 #-------------------> control file size
		File Number=0, Blksiz=16384, File Type=1 CONTROL

the control seq is the following, and it is same with the dump file above “Control Seq=730=0x2da”.

SYS@orcl11g> select CONTROLFILE_SEQUENCE# from v$database;
CONTROLFILE_SEQUENCE#
---------------------
				730
SYS@orcl11g> 

Oracle Control file: database entry

Use level 2 to dump controlfile and get the dumpfile.

alter session set events 'immediate trace name controlf level 2';
select * from v$diag_info where NAME='Default Trace File'; 

Example:

***************************************************************************
DATABASE ENTRY
***************************************************************************
(size = 316, compat size = 316, section max = 1, section in-use = 1,
last-recid= 0, old-recno = 0, last-recno = 0)
(extent = 1, blkno = 1, numrecs = 1)
05/31/2018 11:08:47
DB Name "ORCL11G"
Database flags = 0x00404001 0x00001200    -------------------------> the Database flags is here.
Controlfile Creation Timestamp  05/31/2018 11:08:47
Incmplt recovery scn: 0x0000.00000000
Resetlogs scn: 0x0000.00158c21 Resetlogs Timestamp  05/31/2018 10:58:25
Prior resetlogs scn: 0x0000.00157e15 Prior resetlogs Timestamp  05/31/2018 07:48:51
Redo Version: compatible=0xb200400
#Data files = 8, #Online files = 8
Database checkpoint: Thread=1 scn: 0x0000.00176c36
Threads: #Enabled=1, #Open=1, Head=1, Tail=1
enabled  threads:  01000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000
Max log members = 3, Max data members = 1
Arch list: Head=3, Tail=3, Force scn: 0x0000.00165899scn: 0x0000.00000000
Activation ID: 1084451317
SCN compatibility 1
Auto-rollover enabled
Controlfile Checkpointed at scn:  0x0000.00176c77 06/02/2018 06:29:14
thread:0 rba:(0x0.0.0)
enabled  threads:  00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000 00000000 00000000 00000000

The Database flag meaning are the following list.

KCCDIMRE 0x00000001 whether media recovery enabled(that is: ARCHIVELOG mode)  #------------------->
KCCDICKD 0x00000002 if dictionary must be checked with control file
KCCDIRLR 0x00000004 DB OPEN RESETLOGS required
KCCDIJNK 0x00000008 (junk value from beta)
KCCDIMRC 0x00000010 was/is last mounted READ_COMPATIBLE
KCCDICNV 0x00000020 controlfile was just created by convert from v6
KCCDIIRA 0x00000040 Incomplete Recovery Allowed when resetting logs
KCCDICCF 0x00000100 Controlfile was created with CREATE CONTROLFILE
KCCDIINV 0x00000200 Invalid control file or database; still creating
KCCDISBD 0x00000400 StandBy Database; control file for hot standby
KCCDIORL 0x00000800 Opened ResetLogs; set until dictionary check
KCCDICFC 0x00001000 valid ControlFile Checkpoint in backup cf
KCCDISSN 0x00002000 SnapShot controlfile fileName pointer valid
KCCDIUCD 0x00004000 lazy file header Update Checkpoint cycle Done  #------------------->
KCCDICLO 0x00008000 clone database
KCCDINDL 0x00010000 standby database No Data Loss
KCCDISPK 0x00020000 Supplemental log primary keys
KCCDISUI 0x00040000 Supplemental log unique indexes
KCCDISFK 0x00080000 Supplemental log foreign keys
KCCDIGDA 0x00100000 Database guard all
KCCDIGDS 0x00200000 Database guard standby data
KCCDIIMR 0x00400000 Group Membership Recovery is supported   #------------------->
KCCDIEAR 0x00800000 End-of-redo Archival Received
KCCDISTR 0x01000000 Standby Terminal Recovery
KCCDILSB 0x02000000 Logical StandBy database

So the example”0x00404001 0x00001200”: KCCDIIMR + KCCDIUCD + KCCDIMRE

Another porint: Usually,the control file’s sequence is bigger than the database’s sequence.

SYS@orcl11g> select CONTROLFILE_CHANGE#, CHECKPOINT_CHANGE# from v$database;
CONTROLFILE_CHANGE# CHECKPOINT_CHANGE#
------------------- ------------------
			1535095            1535030
SYS@orcl11g> 

CHECKPOINT PROGRESS RECORDS

Example:PROGRESS RECORDS

***************************************************************************
CHECKPOINT PROGRESS RECORDS
***************************************************************************
(size = 8180, compat size = 8180, section max = 11, section in-use = 0,
last-recid= 0, old-recno = 0, last-recno = 0)
(extent = 1, blkno = 2, numrecs = 11)
THREAD #1 - status:0x2 flags:0x0 dirty:93
low cache rba:(0xf.3.0) on disk rba:(0xf.1a9.0)   #---------------------> 
on disk scn: 0x0000.00176e06 06/02/2018 06:31:28
resetlogs scn: 0x0000.00158c21 05/31/2018 10:58:25
heartbeat: 978332391 mount id: 1085236076
THREAD #2 - status:0x0 flags:0x0 dirty:0
low cache rba:(0x0.0.0) on disk rba:(0x0.0.0)
on disk scn: 0x0000.00000000 01/01/1988 00:00:00
resetlogs scn: 0x0000.00000000 01/01/1988 00:00:00
heartbeat: 0 mount id: 0
THREAD #3 - status:0x0 flags:0x0 dirty:0
low cache rba:(0x0.0.0) on disk rba:(0x0.0.0)
on disk scn: 0x0000.00000000 01/01/1988 00:00:00
resetlogs scn: 0x0000.00000000 01/01/1988 00:00:00
heartbeat: 0 mount id: 0
THREAD #4 - status:0x0 flags:0x0 dirty:0
low cache rba:(0x0.0.0) on disk rba:(0x0.0.0)
on disk scn: 0x0000.00000000 01/01/1988 00:00:00
resetlogs scn: 0x0000.00000000 01/01/1988 00:00:00
heartbeat: 0 mount id: 0

The instance recovery will start from low cache rba to on disk rba when the database is starting.

What is the RBA?

A"Redo Block Address" (RBA) describes a physical location within aredo log file. 
Ref: Question About RBA (Redo Block Address) [ID 759966.1]

There are three parts in RBA.
(1)the log file sequence number (4 bytes)
(2)the log file block number (4 bytes)
(3)the byte offset into the block at which the redo record starts (2bytes)

rba:(0xf.3.0) : the log sequence is "f"->15, Block number is 3, byte offset is 0.

EXTENDED DATABASE ENTRY

***************************************************************************
EXTENDED DATABASE ENTRY
***************************************************************************
(size = 900, compat size = 900, section max = 1, section in-use = 1,
last-recid= 0, old-recno = 0, last-recno = 0)
(extent = 1, blkno = 150, numrecs = 1)
Control AutoBackup date(dd/mm/yyyy)=31/ 5/2018
Next AutoBackup sequence= 0
Database recovery target inc#:1, Last open inc#:1
flg:0x0, flag:0x0
Change tracking state=0, file index=0, checkpoint count=0scn: 0x0000.00000000
Flashback log count=0, block count=0
Desired flashback log size=0 blocks
Oldest guarantee restore point=0
Highest thread enable/disable scn: 0x0000.00158c21
Number of Open thread with finite next SCN in last log: 0
Number of half-enabled redo threads: 0
Sum of absolute file numbers for files currently being moved online: 0

The example of the instance recovery from low cache rba to on disk rba

the Steps are the following.

Shutdown abort the instance and check the low cache rba and on disk rba.

SYS@orcl11g> shu abort;
ORACLE instance shut down.
SYS@orcl11g> startup mount;
ORACLE instance started.
Total System Global Area 1556787200 bytes
Fixed Size                  1364844 bytes
Variable Size             889195668 bytes
Database Buffers          654311424 bytes
Redo Buffers               11915264 bytes
Database mounted.
SYS@orcl11g> 
SYS@orcl11g> alter session set events 'immediate trace name controlf level 2';
Session altered.
SYS@orcl11g> col value for a80
SYS@orcl11g> col name for a20
SYS@orcl11g> select * from v$diag_info where NAME='Default Trace File'; 
INST_ID NAME                 VALUE
---------- -------------------- --------------------------------------------------------------------------------
		1 Default Trace File   /u01/app/oracle/diag/rdbms/orcl11g/orcl11g/trace/orcl11g_ora_1748.trc
SYS@orcl11g> 

The dump file:

[oracle@databasevm001 ~]$ cat /u01/app/oracle/diag/rdbms/orcl11g/orcl11g/trace/orcl11g_ora_1748.trc
Trace file /u01/app/oracle/diag/rdbms/orcl11g/orcl11g/trace/orcl11g_ora_1748.trc
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - Production
~~~~~~~~~~~
***************************************************************************
CHECKPOINT PROGRESS RECORDS
***************************************************************************
(size = 8180, compat size = 8180, section max = 11, section in-use = 0,
last-recid= 0, old-recno = 0, last-recno = 0)
(extent = 1, blkno = 2, numrecs = 11)
THREAD #1 - status:0x2 flags:0x0 dirty:55
low cache rba:(0xf.18b0.0) on disk rba:(0xf.19da.0)   #---------------------->
~~~~~~~~~~~

The RBA: low cache rba:(0xf.18b0.0) on disk rba:(0xf.19da.0)

low cache rba:(0xf.18b0.0)

SYS@orcl11g> select to_number('f','xxxxx') from dual;
TO_NUMBER('F','XXXXX')
----------------------
					15
SYS@orcl11g> select to_number('18b0','xxxxx') from dual;
TO_NUMBER('18B0','XXXXX')
-------------------------
					6320
SYS@orcl11g> 

on disk rba:(0xf.19da.0)

SYS@orcl11g> select to_number('f','xxxxx') from dual;
TO_NUMBER('F','XXXXX')
----------------------
					15
SYS@orcl11g>
SYS@orcl11g> select to_number('19da','xxxxx') from dual;
TO_NUMBER('19DA','XXXXX')
-------------------------
					6618
SYS@orcl11g> 

The instance recovery is from the number redo log file#15 offset#6320 to redo log file#15 offset#6618.

When open the database, the alert logs(alert_orcl11g.log ) are the following.

The recovery process can be found in the alert log files.

SYS@orcl11g> alter database open;

Database altered.

SYS@orcl11g> 
++++++++++++++++++++++++++++++++++++++++++ 
alter database open
Beginning crash recovery of 1 threads
parallel recovery started with 3 processes
Started redo scan
Completed redo scan
read 149 KB redo, 55 data blocks need recovery
Started redo application at
Thread 1: logseq 15, block 6320               #--------------------------------------> low cache rba
Recovery of Online Redo Log: Thread 1 Group 3 Seq 15 Reading mem 0
Mem# 0: /u01/app/oracle/oradata/orcl11g/redo03.log
Completed redo application of 0.03MB
Completed crash recovery at
Thread 1: logseq 15, block 6618, scn 1559118  #--------------------------------------> on disk rba

‘Thread 1: logseq 15, block 6320’ and ‘Thread 1: logseq 15, block 6618’ are the same with the dump control file’s low cache rba on disk rba.

The test of removing control file durning open database status.

Recovery the control file from ckpt process’s fd.

SYS@orcl11g> show parameter control_files
NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
control_files                        string      /u01/app/oracle/oradata/orcl11
												g/control01.ctl, /u01/app/orac
												le/fast_recovery_area/orcl11g/
												control02.ctl
SYS@orcl11g> !cp /u01/app/oracle/oradata/orcl11g/control01.ctl /tmp/control01.ctl
SYS@orcl11g> !cp /u01/app/oracle/fast_recovery_area/orcl11g/control02.ctl /tmp/control02.ctl
SYS@orcl11g> 
SYS@orcl11g> !rm /u01/app/oracle/oradata/orcl11g/control01.ctl  /u01/app/oracle/fast_recovery_area/orcl11g/control02.ctl
SYS@orcl11g> !ps -ef | grep ckpt | grep -v grep
oracle    1730     1  0 07:57 ?        00:00:00 ora_ckpt_orcl11g
SYS@orcl11g> !ls -l /proc/1730/fd
total 0
lr-x------. 1 oracle oinstall 64 Jun  9 08:19 0 -> /dev/null
l-wx------. 1 oracle oinstall 64 Jun  9 08:19 1 -> /dev/null
lrwx------. 1 oracle oinstall 64 Jun  9 08:19 10 -> /u01/app/oracle/product/11.2.0.4/dbhome_1/dbs/lkORCL11G
lr-x------. 1 oracle oinstall 64 Jun  9 08:19 11 -> /u01/app/oracle/product/11.2.0.4/dbhome_1/rdbms/mesg/oraus.msb
l-wx------. 1 oracle oinstall 64 Jun  9 08:19 2 -> /dev/null
lrwx------. 1 oracle oinstall 64 Jun  9 08:19 256 -> /u01/app/oracle/oradata/orcl11g/control01.ctl (deleted)
lrwx------. 1 oracle oinstall 64 Jun  9 08:19 257 -> /u01/app/oracle/fast_recovery_area/orcl11g/control02.ctl (deleted)
lr-x------. 1 oracle oinstall 64 Jun  9 08:19 3 -> /dev/null
lr-x------. 1 oracle oinstall 64 Jun  9 08:19 4 -> /dev/null
lr-x------. 1 oracle oinstall 64 Jun  9 08:19 5 -> /dev/null
lr-x------. 1 oracle oinstall 64 Jun  9 08:19 6 -> /u01/app/oracle/product/11.2.0.4/dbhome_1/rdbms/mesg/oraus.msb
lr-x------. 1 oracle oinstall 64 Jun  9 08:19 7 -> /proc/1730/fd
lr-x------. 1 oracle oinstall 64 Jun  9 08:19 8 -> /dev/zero
lrwx------. 1 oracle oinstall 64 Jun  9 08:19 9 -> /u01/app/oracle/product/11.2.0.4/dbhome_1/dbs/hc_orcl11g.dat
SYS@orcl11g> 
SYS@orcl11g> !cp /proc/1730/fd/256 /u01/app/oracle/oradata/orcl11g/control01.ctl
SYS@orcl11g> !cp /proc/1730/fd/257 /u01/app/oracle/fast_recovery_area/orcl11g/control02.ctl
SYS@orcl11g> 
SYS@orcl11g> shu immediate;
Database closed.
ORA-03113: end-of-file on communication channel
Process ID: 1748
Session ID: 191 Serial number: 3
SYS@orcl11g> 
SYS@orcl11g> startup 
ORA-24324: service handle not initialized
ORA-01041: internal error. hostdef extension doesn't exist
SYS@orcl11g> exit
Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
[oracle@databasevm001 ~]$ sqlplus / as sysdba

SQL*Plus: Release 11.2.0.4.0 Production on Sat Jun 9 08:23:58 2018

Copyright (c) 1982, 2013, Oracle.  All rights reserved.

Connected to an idle instance.

SYS@orcl11g> startup
ORACLE instance started.

Total System Global Area 1556787200 bytes
Fixed Size                  1364844 bytes
Variable Size             889195668 bytes
Database Buffers          654311424 bytes
Redo Buffers               11915264 bytes
Database mounted.
Database opened.
SYS@orcl11g> 

However,there is the attention warning from the alert log and need to re-create the control file.

********************* ATTENTION: ******************** 
The controlfile header block returned by the OS
has a sequence number that is too old. 
The controlfile might be corrupted.
PLEASE DO NOT ATTEMPT TO START UP THE INSTANCE 
without following the steps below.
RE-STARTING THE INSTANCE CAN CAUSE SERIOUS DAMAGE 
TO THE DATABASE, if the controlfile is truly corrupted.
In order to re-start the instance safely, 
please do the following:
(1) Save all copies of the controlfile for later 
	analysis and contact your OS vendor and Oracle support.
(2) Mount the instance and issue: 
	ALTER DATABASE BACKUP CONTROLFILE TO TRACE;
(3) Unmount the instance. 
(4) Use the script in the trace file to
	RE-CREATE THE CONTROLFILE and open the database. 
*****************************************************
USER (ospid: 1748): terminating the instance
Sat Jun 09 08:21:47 2018
System state dump requested by (instance=1, osid=1718 (DIAG)), summary=[abnormal instance termination].
System State dumped to trace file /u01/app/oracle/diag/rdbms/orcl11g/orcl11g/trace/orcl11g_diag_1718_20180609082147.trc
Dumping diagnostic data in directory=[cdmp_20180609082147], requested by (instance=1, osid=1718 (DIAG)), summary=[abnormal instance termination].
Instance terminated by USER, pid = 1748

The best ways to recovery control file can be referenced the other doucments…

To be continue….

Have a good life! 2018/06 via LinHong


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