Current log sequence number

i have a small doubt :
when there is log switch , the current log sequence number is stored in the control file . Is the same current log sequence number stored in the headers of the datafiles??????
waiting for your answers eargerly.....
kumaresan.M

nops i don think so.
there is no need for doing this, only controlfile needs to know about the current sequence number
Regards

Similar Messages

Doubt about CURRENT LOG SEQUENCE NUMBER

I just want to know that why the "current log sequence number" is added to the header of each data file ? why oracle needs to do that ? as it is also added to the control file and whenever it needs to know the current log sequence number , it can get it from control file , then why to add this in the header of data files ?

For Recovery.
When you are doing a Recovery of a database where the datafiles have been restored from backups but the controlfile has been recreated (thus, the controlfile has no information about log sequence numbers and checkpoint scns), the Recovery must read this information from the datafile headers.
Say you have 5 datafiles and they have been backed up 6 months ago using ALTER TABLESPACE BEGIN BACKUP commands and, therefore, have different checkpoint SCNs. The checkpoint SCNs could be 1021, 1059, 1085, 1745, 2045.
How would Oracle know which Log Sequence Numbers are needed ? It knows that a Recovery must start with SCN 1021. But if the information about Log Sequence Numbers is not available in the controlfile (either because it is as of today and the controlfile doesn't store information about 6 months of redo logs OR because the controlfile has been recreated), what is the Log Sequence Number corresponding to that SCN 1021 ?
That information is available in the datafile header. You will NOT see it in V$DATAFILE or V$DATAFILE_HEADER. You will not see it in a level 1 dump of datafile headers.
You will see an example here :
http://web.singnet.com.sg/~hkchital/Incomplete_Recovery_with_BackupControlfile.doc
Hemant K Chitale
http://hemantoracledba.blogspot.com

Redo log sequence number

hi everyone,
I am looking at our SB system, and try to do only redo log backup. however it comes back with error message: The current redo log sequence number is not greater than the sequence number of the last saved offline redo log file.
So, we suspect that since last refresh, we may reset the sequence back from 1. Any one know how to solve this problem? Thanks in advance.
Amy

Hi,
Is your probh solved?
Can u pl tell if u executed a recovery of database earlier?
Pl check if there was a case of reset logs.
To do this run BRTOOLS-->Instance Mgt->Show Inst Status.
This will show if there was a case of reset logs.
If it is so try the following:
Shut down sap and the database.
Look for a folder named oraarch
Oracle/sid/oraarch
Copy all the archive files to another folder and delete all the arc files from the oraarch folder.
The name of the arch files will be like <SID>ARCHARC123456.001
After copying to another location and subsequently deleting them from oraarch folders start up oracle in mount mode.
Then issue the following sql
alter database open resetlogs;
then start sap.
NB:Dont forget to take a complete backup before and after diong this.
Hope this will help.
Most probably your database contains two icarnations of redo log files so this error is comming.
regards

Log sequence number

who updates the log sequence number in control file and datafiles , I know chkpoint is responsible to update checkpoint number in datafile and control file number.

it is LGWR.

Who writes LOG SEQUENCE NUMBER to CONTROL FILE,whether CKPT or LGWR process

I am in confusion that,
When log switch occurs that time Log sequence no. is generated by LGWR. then after who writes that LSN to CONTROL FILE whether Checkpoint or LGWR.
Please provide me proper answer with example.....

I notice by using fuser on a controlfile on hp-ux, a number of processes keep the controlfile open. So it would make sense that the one that writes logs would write log sequence numbers to the controlfile too.
$ for z in `/usr/sbin/fuser control03.ctl|awk ' {x=split($0,args); for (i=2;i<=x;i++){print args[i]}}'`
        do
            ps -efx|grep $z|grep -v grep
        done
control03.ctl: oooooooooo
oracle 27129     1 0 Sep 5 ?        12:15 ora_arc1_TPRD
oracle 27073     1 0 Sep 5 ?        52:45 ora_dbw0_TPRD
oracle 27127     1 0 Sep 5 ?        10:52 ora_arc0_TPRD
oracle 9485     1 0 Nov 3 ?         9:14 oracleTPRD (LOCAL=NO)
oracle 22395     1 0 08:36:22 ?         0:24 oracleTPRD (LOCAL=NO)
oracle 27075     1 0 Sep 5 ?        68:53 ora_lgwr_TPRD
oracle 22116     1 0 08:33:24 ?         1:06 oracleTPRD (LOCAL=NO)
oracle 27077     1 0 Sep 5 ?        41:05 ora_ckpt_TPRD
oracle 26510     1 0 Nov 30 ?        21:26 oracleTPRD (LOCAL=NO)

Command that give me the log sequence number of Specifc date

hi,
I need a command that gives me the LSN number of previous date. e.g if current date is 20-02-2013. & i want to get the LSN number that have date last month.28-01-2013.
thanks.
Regards,

No Replies

Generate archive logs are not in sequence number?

On last friday... the latest archive log number was ARC00024.ARC. Tomorrow when I come backup, the archive logs ARC00001.ARC and ARC00002.ARC were being generated by oracle itself. I wondering the archive log sequence should be in sequence. What is happening?
SQL> archive log list;
Database log mode Archive Mode
Automatic archival Enabled
Archive destination C:\oracle\ora92\RDBMS
Oldest online log sequence 1
Next log sequence to archive 3
Current log sequence 3
SQL>
FAN
Edited by: user623471 on Jun 7, 2009 7:35 PM

khurram,
Its our production instance and havent issued resetlogs option but when listing the arvchives it shows in different sequence number...
and also while copying the archives by RMAN it doesnt copy in sequence
-rw-r----- 1 xxx dba 69363859 May 28 19:16 2_10373.arc.gz
-rw-r----- 1 xxx dba 43446622 May 28 19:16 1_10553.arc.gz
-rw-r----- 1 xxx dba 52587365 May 28 19:16 1_10578.arc.gz
-rw-r----- 1 xxx dba 45251820 May 28 19:16 1_10543.arc.gz
-rw-r----- 1 xxx dba 60890256 May 28 19:17 1_10579.arc.gz
-rw-r----- 1 xxx dba 46659008 May 28 19:17 1_10548.arc.gz
-rw-r----- 1 xxx dba 116899466 May 28 19:17 2_10353.arc.gz
-rw-r----- 1 xxx dba 77769517 May 28 19:17 1_10531.arc.gz
-rw-r----- 1 xxx dba 66401923 May 28 19:18 1_10530.arc.gz
-rw-r----- 1 xxx dba 45972697 May 28 19:18 1_10605.arc.gz
-rw-r----- 1 xxx dba 55082543 May 28 19:18 1_10600.arc.gz
-rw-r----- 1 xxxq dba 42682207 May 28 19:19 1_10547.arc.gz
thanks,
baskar.l

In standby db, can't find sequence number of Last Applied Log.

Hello,
Standby database is behind the primary database for over 200 hours, to repaire this, we are using a incremental backup from primary database and a restored control file.
after starting up standby database, in Grid Control (OEM), can't find "last applied log" sequence number,
go to that standby, do
standby> select max(sequence#) from v$archived_log where applied='YES';
MAX(SEQUENCE#)
go to primary,
do
SQL> select max(sequence#) from v$archived_log where applied='YES';
MAX(SEQUENCE#)
83833
then using OEM grid control, to Verify checks various standby database settings.
Initializing
Connected to instance standby_server:standby
Starting alert log monitor...
Updating Data Guard link on database homepage...
Skipping verification of fast-start failover static services check.
Data Protection Settings:
Protection mode : Maximum Performance
Redo Transport Mode settings:
primary.com: ASYNC
standby.com: ASYNC
Checking standby redo log files.....OK
Checking Data Guard status
primary.com : Normal
standby.com : Normal
Checking inconsistent properties
Checking agent status
Checking applied log on standby........WARNING:
Timed out after 60 seconds waiting for log to be applied.
Processing completed.
so how to fix this?
thanks you very much.
Edited by: 951932 on Oct 18, 2012 7:44 AM

Hello;
Probably nothing to fix. This is a common warning message.
It even occurs in this example :
http://www.databasejournal.com/features/oracle/article.php/10893_3826706_2/Oracle-11g-Data-Guard-Grid-Control-Management.htm
Best Regards
mseberg

Archive sequence number from standby does not match primary

I have two unix servers configured, one as primary and one as standby, both in 11.2.0.2. When I run the verification scripts, I noticed that my standby's archive log sequence does not match the primary.
From standby:
select database_role, open_mode from v$database; Result: PHYSICAL STANDBY, MOUNTED
select max(sequence#) from v$archived_log; Result is null
archive log list;Database log mode Archive Mode
Automatic archival Enabled
Archive destination /arch/standby
Oldest online log sequence 0
Next log sequence to archive 0
Current log sequence 0

Hello;
I don't think you have Data Guard working.
select max(sequence#) from v$archived_log; This should return a number.
Do an alter system switch logfile; on the primary, I'm thinking the new log never makes it to your standby.
Once you have this working consider running something like this from your Primary:
SELECT name as STANDBY, SEQUENCE#, applied, completion_time from v$archived_log WHERE DEST_ID = 2 AND NEXT_TIME > SYSDATE -1;
select max(sequence#) from v$archived_log where NEXT_TIME > sysdate -1;
You can change the first query to include both the Primary and the Standby.
Best Regards
mseberg

Log sequence difference among RAC Instances

RDBMS Version : 11.2
Platform : Solaris 10
In our RAC DB, we have 6 redo logs.
SQL> select * from v$logfile order by 1,2;
    GROUP# STATUS TYPE    MEMBER                                                                    IS_
         1         ONLINE +ORCL_ARCH01/ORCL_ARCH/orcl_log01.dbf                                     NO
         2         ONLINE +ORCL_ARCH01/ORCL_ARCH/orcl_log02.dbf                                     NO
         3         ONLINE +ORCL_ARCH01/ORCL_ARCH/orcl_log03.dbf                                     NO
         4         ONLINE +ORCL_ARCH01/ORCL_ARCH/orcl_log04.dbf                                     NO
         5         ONLINE +ORCL_ARCH01/ORCL_ARCH/orcl_log05.dbf                                     NO
         6         ONLINE +ORCL_ARCH01/ORCL_ARCH/orcl_log06.dbf                                     NO
6 rows selected.
Logically or shall I say 'internally' , 3 redo logs are allocated per thread. But they all belong to one database.
SQL> select group#,thread#,members from v$log order by 1,2;
    GROUP#    THREAD#    MEMBERS
         1          1          1
         2          1          1
         3          1          1
         4          2          1
         5          2          1
         6          2          1
6 rows selected.
SQL> exit;If all these 6 redo log files belong to one database, then why do they have different max (sequence#) ?
ie. The 'Oldest online log sequence' in Node1 shows 3432 and
     ''Oldest online log sequence' in Node2 shows 3188 (a difference of 244 )
-- Instance1 in Node1
SQL> archive log list
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            +ORCL_ARCH01/ORCL_ARCH
Oldest online log sequence     3432 ------------------------->
Next log sequence to archive   3434
Current log sequence           3434
-- Instance 2 in Node2
SQL> archive log list
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            +ORCL_ARCH01/ORCL_ARCH
Oldest online log sequence     3188   ------------------------> ( 3432 - 3188 = 244)
Next log sequence to archive   3190
Current log sequence           3190

So, this means Node1 is more loaded than Node2 ?
So, in a properly configured RAC set both instances should show almost similar number for 'Oldest online log sequence' ? (ignoring the manual switches)

Thread 1 advanced to log sequence (redo log)

Hi All,
db:oracle 10gR2(10.2.0.4)
os:solaris10
My alert log file shows following information all the time....can you please explain me whats going on??
Mon Jan 30 01:40:30 2012
Thread 1 advanced to log sequence 253305
Current log# 2 seq# 253305 mem# 0: C:\ORACLE\PRODUCT\10.2.0\ORADATA\JNPC\REDO02.LOG
Mon Jan 30 01:45:40 2012
Thread 1 advanced to log sequence 253306
Current log# 3 seq# 253306 mem# 0: C:\ORACLE\PRODUCT\10.2.0\ORADATA\JNPC\REDO03.LOG
Mon Jan 30 01:51:21 2012
Thread 1 advanced to log sequence 253307
Current log# 1 seq# 253307 mem# 0: C:\ORACLE\PRODUCT\10.2.0\ORADATA\JNPC\REDO01.LOG
Mon Jan 30 01:56:53 2012
Thread 1 advanced to log sequence 253308
Current log# 2 seq# 253308 mem# 0: C:\ORACLE\PRODUCT\10.2.0\ORADATA\JNPC\REDO02.LOG
Mon Jan 30 02:01:57 2012
Thread 1 advanced to log sequence 253309
Current log# 3 seq# 253309 mem# 0: C:\ORACLE\PRODUCT\10.2.0\ORADATA\JNPC\REDO03.LOG
Mon Jan 30 02:06:31 2012
Thread 1 advanced to log sequence 253310
Current log# 1 seq# 253310 mem# 0: C:\ORACLE\PRODUCT\10.2.0\ORADATA\JNPC\REDO01.LOG
Mon Jan 30 02:11:37 2012
Thread 1 advanced to log sequence 253311
Current log# 2 seq# 253311 mem# 0: C:\ORACLE\PRODUCT\10.2.0\ORADATA\JNPC\REDO02.LOG
Mon Jan 30 02:16:44 2012
Thread 1 advanced to log sequence 253312
Current log# 3 seq# 253312 mem# 0: C:\ORACLE\PRODUCT\10.2.0\ORADATA\JNPC\REDO03.LOG
Mon Jan 30 02:21:51 2012
Thread 1 advanced to log sequence 253313
Current log# 1 seq# 253313 mem# 0: C:\ORACLE\PRODUCT\10.2.0\ORADATA\JNPC\REDO01.LOG
Mon Jan 30 02:27:11 2012
Thread 1 advanced to log sequence 253314
Current log# 2 seq# 253314 mem# 0: C:\ORACLE\PRODUCT\10.2.0\ORADATA\JNPC\REDO02.LOG
Mon Jan 30 02:32:31 2012
Thread 1 advanced to log sequence 253315
Current log# 3 seq# 253315 mem# 0: C:\ORACLE\PRODUCT\10.2.0\ORADATA\JNPC\REDO03.LOG
Mon Jan 30 02:37:25 2012
Thread 1 advanced to log sequence 253316
Current log# 1 seq# 253316 mem# 0: C:\ORACLE\PRODUCT\10.2.0\ORADATA\JNPC\REDO01.LOG
Mon Jan 30 02:42:15 2012
Thread 1 advanced to log sequence 253317
Current log# 2 seq# 253317 mem# 0: C:\ORACLE\PRODUCT\10.2.0\ORADATA\JNPC\REDO02.LOG
Mon Jan 30 02:47:05 2012
Thread 1 advanced to log sequence 253318
Current log# 3 seq# 253318 mem# 0: C:\ORACLE\PRODUCT\10.2.0\ORADATA\JNPC\REDO03.LOG
I appreciate your response......
thanks.

This information shows that the log switch has occured.
The LGWR writes the redo information from the redo log buffer to the online redo log file. When the current online redo log file fills, LGWR begins writing to the next available online redo log file. In the mean time, the ARC process archives the contents of the filled online redo log file (If the database is in archivelog mode. If its in noarchive mode, then the filled online redo log file would not be archived). These archives are given a unique log sequence number.
In your case 253305, 253306..are the log sequence numbers.
You can refer http://docs.oracle.com/cd/B10501_01/server.920/a96521/onlineredo.htm for a detailed information

Next log sequence to archive in Standby Database (RAC Dataguard Issue)

Hi All,
I just had implemented Data Guard in our server. My primary Database is RAC configured, but it is only single node. The other Instance was removed and converted it to Developement Instance. For the reason I kept the primary as RAC is when I will implement dataguard, my Primary Database is RAC with 7 nodes.
The first test is successful, and I was able to "switchover" from my primary to standby. I failed in the 'FAILOVER" test.
I restore my primary server and redo the setup.
BTW, my standby DB is physical standby.
When I try to switchover again and issue archive log list, below is my output.
SQL> archive log list;
Database log mode Archive Mode
Automatic archival Enabled
Archive destination USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence 38
*Next log sequence to archive 0*
Current log sequence 38
SQL> select open_mode, database_role from v$database;
OPEN_MODE DATABASE_ROLE
MOUNTED PHYSICAL STANDBY
===============================================
SQL> archive log list;
Database log mode Archive Mode
Automatic archival Enabled
Archive destination USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence 38
*Next log sequence to archive 38*
Current log sequence 38
SQL> select open_mode, database_role from v$database;
OPEN_MODE DATABASE_ROLE
READ WRITE PRIMARY
In my first attempt to switchover before I failed in "FAILOVER" test, I also issue +archive log list+ in both primary and standby database, and if I remember it right, next log sequence on both should be identical. Am I right on this?
Thanks in Advance.
Jay A

Or Am i just overthinking on this?
Is dataguard only looking for the current and oldest log sequence?

Very Urgent: Thread 1 cannot allocate new log, sequence 6 : Script stuck

I am running one script, it is stuck with log file showing:
Thread 1 cannot allocate new log, sequence 6
All online logs needed archiving
Current log# 7 seq# 5 mem# 0: /u13/sjmarte/oradata/redo7a.log
I have checked the database: it is in archivelog mode
Checked the archvie dest: we have space in TB's
And almost 24GB's occupied by log files each of 6GB's.
====================================
Can any one please help us how to get rid of this issue

Sorry I m new to this forum.
We dont have a seperate FRA in this case.
This is the log file information:
Wed May 18 13:28:23 2011
Thread 1 advanced to log sequence 5 (LGWR switch)
Current log# 7 seq# 5 mem# 0: /u13/sjmarte/oradata/redo7a.log
Current log# 7 seq# 5 mem# 1: /u14/sjmarte/oradata/redo7b.log
Wed May 18 13:31:58 2011
ORACLE Instance sjmarte - Can not allocate log, archival required
Wed May 18 13:31:58 2011
Thread 1 cannot allocate new log, sequence 6
All online logs needed archiving
Current log# 7 seq# 5 mem# 0: /u13/sjmarte/oradata/redo7a.log
Current log# 7 seq# 5 mem# 1: /u14/sjmarte/oradata/redo7b.log
Here is archive log list
SQL> archive log list
Database log mode Archive Mode
Automatic archival Enabled
Archive destination /backup/oracle/sjmarte/archive
Oldest online log sequence 2
Next log sequence to archive 2
Current log sequence 5
Edited by: 784786 on May 18, 2011 11:35 AM

Next log sequence to archive is different

Hi,
I have doubt on standby (DR) concept.
I can see that in my standby database next log sequence to archive shows 0.
Is this ok or something is wrong?
PRODUCTION
SQL> archive log list;
Database log mode Archive Mode
Automatic archival Enabled
Archive destination /u006/app/archive/XXPROD/arch
Oldest online log sequence 2627
Next log sequence to archive 2631
Current log sequence 2631
STANDBY
SQL> archive log list;
Database log mode Archive Mode
Automatic archival Enabled
Archive destination /u006/app/archive/XXPROD/arch
Oldest online log sequence 2627
Next log sequence to archive 0
Current log sequence 2631

Hello;
Short answer no nothing is wrong.
Its the same on mine :
SQL> archive log list;
Database log mode              Archive Mode
Automatic archival             Enabled
Archive destination            USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence     5069
Next log sequence to archive   0
Current log sequence           5071
SQL> I use v$archived_log to check mine standby :
SELECT name as STANDBY, SEQUENCE#, applied, completion_time from v$archived_log WHERE DEST_ID = 2 AND NEXT_TIME > SYSDATE -1;Against my Primary I get the last log :
select max(sequence#) from v$archived_log where NEXT_TIME > sysdate -1;Data Guard has a set of v$ views to check results, 8archive log list8 isn't so good since with Data Guard you have two copies of the same database in different roles.
Another query I like is : (Run on the standby)
select process, status, sequence#, block# from v$managed_standby;The Oracle doc E10700-02 has several example in chapter 9 "Monitoring Primary, Physical Standby, and Snapshot Standby Databases"
Also section "3.2.7 Verify the Physical Standby Database Is Performing Properly"
Best Regards
mseberg

ARC0: Warning. Log sequence in archive filename wrapped

Hi,
I am having my production database(Oracle 11gR1) in windows 2003 server.
I am often getting below archive warnings in alert logs.
ARC0: Warning. Log sequence in archive filename wrapped
to fix length as indicated by %S in LOG_ARCHIVE_FORMAT.
Old log archive with same name might be overwritten.
1.Could any one tell the reason and how to resolve this?
2.Also i want to know the limitations of %s and %S in LOG_ARCHIVE_FORMAT?
my log_archive_format is set to string ARC%S_%R.%T

Vikash Jain (DBA Trainee) wrote:
Hi,
I am having my production database(Oracle 11gR1) in windows 2003 server.
I am often getting below archive warnings in alert logs.
ARC0: Warning. Log sequence in archive filename wrapped
to fix length as indicated by %S in LOG_ARCHIVE_FORMAT.
Old log archive with same name might be overwritten.
1.Could any one tell the reason and how to resolve this?
2.Also i want to know the limitations of %s and %S in LOG_ARCHIVE_FORMAT?
my log_archive_format is set to string ARC%S_%R.%T
Change log archive format to small(s) *%s* instead of *%S*
%S Specifies the log sequence number. This number is padded to the left by
zeroes. The default value is one with a range of up to five characters.
%s Specifies the log sequence number. The number is not padded. The default
value is one with no range limit on characters. also refer this link http://docs.oracle.com/cd/B19306_01/server.102/b14237/initparams103.htm

Current log sequence number

Similar Messages

Maybe you are looking for