Oracle Redo Log Activity

Hi Members,
I have an Oracle database instance where the log files continue to grow even where there is no activity from application usage.
What I have noticed that there appears to be some frequency pattern as to when this log activity occurs.
My question is, Are there any default Oracle processes or scheduled jobs that will result in this log data generation.
Thanks
Alan

Hi
You will have many background processes running and they generate text logs. You have e.g. MMON, automatic backups (when enabled), in 11g you have autotask process which will tune top sqls, gather stats etc. So even when nobody connects to the db you will still see some activities there.
Paul

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    请把alert.log 和 最近的AWR发给我
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  • GoldenGate Extract Process will not read from redo log with manual help

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  • Oracle 10g R2 Database Redo Log Files

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    Waheed,
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  • How to change redo log size in oracle 10g

    Hi Experts,
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    Amit

    Dear Amit,
    You can enlarge the size of existing Online Redo log files, by adding new groups with different size of files (origlog$/mirrlog$) and then carefully droping the old groups with  their associated inactive files.
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                                 /origlogA                  /mirrlogA            
    15                        log_g15m1.dbf         log_g15m2.dbf               100 MB
    17                        log_g17m1.dbf            log_g17m2.dbf               100 MB
                                /origlogB                    /mirrlogB
    16                       log_g16m1.dbf          log_g16m2.dbf            100 MB
    18                       log_g18m1.dbf            log_g18m2.dbf            100 MB
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  • How to know the delay in redo log apply on Active Dataguard 11g

    Hello All,
    How to know the delay in redo log apply on Active Dataguard 11g...
    Do we need to wait till log switch occurs?
    Or is it recommended to schedule a log switch every 15 min, no matter data is updated/inserted or not in primary?
    Please suggest...
    Oracle : oracle 11g Release 2
    OS : RHEL 5.4
    Thanks
    Edited by: user1687821 on Feb 23, 2012 12:02 AM

    Hello CKPT,
    Thank you for the valuable information...
    We have not configured databroker.
    Output of the query
    SELECT * FROM (
    SELECT sequence#, archived, applied,
    TO_CHAR(completion_time, 'RRRR/MM/DD HH24:MI') AS completed
    FROM sys.v$archived_log
    ORDER BY sequence# DESC)
    WHERE ROWNUM <= 10
    Primary...
    SEQUENCE#     ARCHIVED     APPLIED     COMPLETED
    29680          YES          YES     2012/02/23 01:11
    29680          YES          NO     2012/02/23 01:11
    29679          YES          NO     2012/02/22 23:11
    29679          YES          YES     2012/02/22 23:11
    29678          YES          YES     2012/02/22 23:11
    29678          YES          NO     2012/02/22 23:11
    29677          YES          YES     2012/02/22 22:32
    29677          YES          NO     2012/02/22 22:32
    29676          YES          YES     2012/02/22 22:02
    29676          YES          NO     2012/02/22 22:02
    Standby...
    SEQUENCE# ARC APP COMPLETED
    29680 YES YES 2012/02/23 01:11
    29679 YES YES 2012/02/22 23:11
    29678 YES YES 2012/02/22 23:11
    29677 YES YES 2012/02/22 22:32
    29676 YES YES 2012/02/22 22:02
    29675 YES YES 2012/02/22 21:24
    29674 YES YES 2012/02/22 19:24
    29673 YES YES 2012/02/22 18:59
    29672 YES YES 2012/02/22 17:42
    29671 YES YES 2012/02/22 17:41
    Primary shows yes as well as no...
    Next,
    From primary:-
    SQL> select thread#,max(sequence#) from v$archived_log group by thread#;
    THREAD#     MAX(SEQUENCE#)
    1     29680
    From standby:-
    SQL> select thread#,max(sequence#) from v$archived_log where applied='YES' group by thread#;
    THREAD# MAX(SEQUENCE#)
    1 29680
    What is the redo transport service you are using? is it LGWR or ARCH ?
    Output of query select * from v$parameter where name like 'log_archive_dest_2' shows below value...
    SERVICE=b_stdb LGWR ASYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=b_stdb
    So is it lgwr already configured...? if yes then how do i see the delay in both servers..
    Yes, the network is good as they both resides in same LAN within same rack
    Thanks...

  • Open database if an active online redo log is missing

    Hi,
    Sorry for the rather long post, but I specified all the steps I performed and couldn't make it shorter :-(
    I need an advice on how to open the database if an active online redo log is missing.
    For test purposes I intentionally performed a shutdown abort when the redo log group 1 was in active state and then renamed its only member (REDO01.LOG) so that the database couldn't perform crash recovery using it. Then upon startup I obviously got the message:
    ORA-00313: open failed for members of log group 1 of thread 1
    ORA-00312: online log 1 thread 1: 'H:\ORADATA\TESTDB\REDO01.LOG'
    ORA-27041: unable to open file
    OSD-04002: unable to open file
    O/S-Error: (OS 2) The system cannot find the file specified.Ok, so I checked the state of the logs:
    {noformat}
    SQL>SELECT a.GROUP#, first_change#, SEQUENCE#, a.status, SUBSTR(b.MEMBER, 1, 40) MEMBER, b.status mem_status, a.archived
      2    FROM v$log a, v$logfile b
      3   WHERE a.GROUP# = b.GROUP#
      4  ORDER BY a.GROUP#, b.MEMBER;
    GROUP# FIRST_CHANGE#  SEQUENCE# STATUS           MEMBER                         MEM_STA ARC
         1        592134         29 ACTIVE           H:\ORADATA\TESTDB\REDO01.LOG           YES
         2        592268         30 CURRENT          C:\ORADATA\TESTDB\REDO02.LOG           NO
         3        592129         28 ACTIVE           C:\ORADATA\TESTDB\REDO03.LOG           YES
    {noformat}Since opening the database to perform a log switch and thus change the status of the redo log group 1 from ACTIVE to INACTIVE to recreate the member isn't possible, I performed database recovery.
    SQL>recover database until cancel;
    ORA-00279: change 592129 generated at 02/04/2009 10:31:15 needed for thread 1
    ORA-00289: suggestion : C:\ORACLE\PRODUCT\10.2.0\FLASH_RECOVERY_AREA\TESTDB\ARCHIVELOG\2009_02_04\O1_MF_1_28_%U_.ARC
    ORA-00280: change 592129 for thread 1 is in sequence #28
    Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
    ORA-00279: change 592134 generated at 02/04/2009 10:31:28 needed for thread 1
    ORA-00289: suggestion : C:\ORACLE\PRODUCT\10.2.0\FLASH_RECOVERY_AREA\TESTDB\ARCHIVELOG\2009_02_04\O1_MF_1_29_%U_.ARC
    ORA-00280: change 592134 for thread 1 is in sequence #29
    ORA-00278: log file 'C:\ORACLE\PRODUCT\10.2.0\FLASH_RECOVERY_AREA\TESTDB\ARCHIVELOG\2009_02_04\O1_MF_1_28_4RLR3JS9_.ARC' no longer needed for this rec
    overy
    Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
    'C:\ORACLE\PRODUCT\10.2.0\FLASH_RECOVERY_AREA\TESTDB\ARCHIVELOG\2009_02_04\O1_MF_1_29_4RLR4MF3_.ARC'
    ORA-00279: change 592268 generated at 02/04/2009 10:32:03 needed for thread 1
    ORA-00289: suggestion : C:\ORACLE\PRODUCT\10.2.0\FLASH_RECOVERY_AREA\TESTDB\ARCHIVELOG\2009_02_04\O1_MF_1_30_%U_.ARC
    ORA-00280: change 592268 for thread 1 is in sequence #30
    ORA-00278: log file 'C:\ORACLE\PRODUCT\10.2.0\FLASH_RECOVERY_AREA\TESTDB\ARCHIVELOG\2009_02_04\O1_MF_1_29_4RLR4MF3_.ARC' no longer needed for this rec
    overy
    Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
    'C:\ORADATA\TESTDB\REDO02.LOG'
    Log applied.
    Media recovery complete.
    SQL>So for log sequence #28 I accepted the proposed archived redo log in the FRA, for sequence #29 (that's the online redo log that is missing!) I manually specified its archived copy, and for sequence #30 I specified the CURRENT online redo log. And as it seems the media recovery was successful.
    Next I tried to open the database but again got the error:
    SQL>alter database open noresetlogs;
    alter database open noresetlogs
    ERROR at line 1:
    ORA-00313: open failed for members of log group 1 of thread 1
    ORA-00312: online log 1 thread 1: 'H:\ORADATA\TESTDB\REDO01.LOG'
    ORA-27041: unable to open file
    OSD-04002: unable to open file
    O/S-Error: (OS 2) The system cannot find the file specified.
    The status of the log groups and its members is exactly as it was in the first query I wrote above, i.e. the redo log group 1 is still ACTIVE, so it's needed for crash recovery (which I had already done manually if I understand correctly how Oracle works!). I also checked if the datafiles are inconsistent (described in metalink doc id 1015544.102):
    SQL>SELECT DISTINCT CHECKPOINT_CHANGE#, FUZZY FROM V$DATAFILE_HEADER;
    CHECKPOINT_CHANGE# FUZ
                592269 NOSo, everything seems ok as far as datafile consistency is concerned.
    My question is: how can I rename/drop/clear/whatever the member of redo log group 1 to open the database?
    I tried to rename the log file member, to add another member to it, to open the database with resetlogs, to clear the logfile group 1, but all without success:
    1)
    SQL>alter database clear logfile group 1;
    alter database clear logfile group 1
    ERROR at line 1:
    ORA-01624: log 1 needed for crash recovery of instance testdb (thread 1)
    ORA-00312: online log 1 thread 1: 'H:\ORADATA\TESTDB\REDO01.LOG'
    2)
    SQL>alter database open resetlogs;
    alter database open resetlogs
    ERROR at line 1:
    ORA-01139: RESETLOGS option only valid after an incomplete database recovery
    3)
    SQL>alter database rename file 'H:\ORADATA\TESTDB\REDO01.LOG' to 'C:\ORADATA\TESTDB\REDO01.LOG';
    alter database rename file 'H:\ORADATA\TESTDB\REDO01.LOG' to 'C:\ORADATA\TESTDB\REDO01.LOG'
    ERROR at line 1:
    ORA-01511: error in renaming log/data files
    ORA-01512: error renaming log file H:\ORADATA\TESTDB\REDO01.LOG - new file C:\ORADATA\TESTDB\REDO01.LOG not found
    ORA-27041: unable to open file
    OSD-04002: unable to open file
    O/S-Error: (OS 2) The system cannot find the file specified.
    4)
    SQL>alter database add logfile member 'C:\ORADATA\TESTDB\REDO01.LOG' to group 1;
    alter database add logfile member 'C:\ORADATA\TESTDB\REDO01.LOG' to group 1
    ERROR at line 1:
    ORA-00313: open failed for members of log group 1 of thread 1
    ORA-00312: online log 1 thread 1: 'H:\ORADATA\TESTDB\REDO01.LOG'
    ORA-27041: unable to open file
    OSD-04002: unable to open file
    O/S-Error: (OS 2) The system cannot find the file specified.Sorry again for the long post and thank you in advance for any suggestion.
    Regards,
    Jure

    You could check if the recovery was complete by (re)creating the controlfile with the resetlogs option.
    <CREATE CONTROLFILE REUSE DATABASE define_db_name RESETLOGS NOARCHIVELOG
    ...>Thanks for the hint. If possible, could you only check if the steps I'm going to perform are ok.
    I did an "alter database backup controlfile to trace;" and then extracted the create controlfile definition part. So in essence I should run the following statements:
    CREATE CONTROLFILE REUSE DATABASE "TESTDB" RESETLOGS  ARCHIVELOG
        MAXLOGFILES 16
        MAXLOGMEMBERS 3
        MAXDATAFILES 100
        MAXINSTANCES 8
        MAXLOGHISTORY 292
    LOGFILE
      GROUP 1 'C:\ORADATA\TESTDB\REDO01.LOG'  SIZE 20M,
      GROUP 2 'C:\ORADATA\TESTDB\REDO02.LOG'  SIZE 20M,
      GROUP 3 'C:\ORADATA\TESTDB\REDO03.LOG'  SIZE 20M
    -- STANDBY LOGFILE
    DATAFILE
      'C:\ORACLE\PRODUCT\10.2.0\ORADATA\TESTDB\SYSTEM01.DBF',
      'C:\ORACLE\PRODUCT\10.2.0\ORADATA\TESTDB\UNDOTBS01.DBF',
      'C:\ORACLE\PRODUCT\10.2.0\ORADATA\TESTDB\SYSAUX01.DBF',
      'C:\ORACLE\PRODUCT\10.2.0\ORADATA\TESTDB\USERS01.DBF'
    CHARACTER SET EE8MSWIN1250
    ALTER DATABASE OPEN RESETLOGS;
    ALTER TABLESPACE TEMP ADD TEMPFILE 'C:\ORACLE\PRODUCT\10.2.0\ORADATA\TESTDB\TEMP01.DBF' REUSE;Is that correct?
    About the RMAN backups: Wouldn't a 'CATALOG RECOVERY AREA' populate the controlfile with backup information again (I'm not using a recovery catalog in this case)?
    Thanks for the help!
    Regards,
    Jure

  • When occurs crash recovery,why use active online redo log not archived log?

    If current redo log had archived, but it's still 'ACTIVE'. As we all know, archived log is just an archived copy of the current redo log which is still 'ACTIVE', they have the same data. But why use active online redo log not archived log for crash recovery?(I think, if crash recovery can use archived log, then whether the online redo log is 'ACTIVE' or not, it can be overwritten)
    Quote:
    Re: v$log : How redo log file can have a status ACTIVE and be already archived?
    Hemant K Chitale
    If your instance crashes, Oracle attempts Instance Recovery -- reading from the Online Redo Logs. It doesn't need ArchiveLogs for Instance Recovery.
    TanelPoder
    Whether the log is already archived or not doesn't matter here, when the instance crashes, Oracle needs some blocks from that redolog. Archivelog is just an archived copy of the redolog, so you could use either the online or achive log for the recovery, it's the same data in there (Oracle reads the log/archivelog file header when it tries to use it for recovery and validates whether it contains the changes (RBA range) in it what it needs).

    Aman.... wrote:
    John,
    Are you sure that the instance recovery (not the media recovery) would be using the archived redo logs? Since the only thing that would be lost is the isntance, there wouldn't be any archived redo log generated from the Current redo log and the previous archived redo logs, would be already checkpointed to the data file, IMHO archived redo logs won't participate in the instance recovery process. Yep, shall watch the video but tomorrow .
    Regards
    Aman....
    That's what I said. Or meant to say. If Oracle used archivelogs for instance recovery, it would not be possible to recover in noarchive log mode. So recovery relies exclusively on the online log.
    Sorry I wasted your time, I'll try to be less ambiguous in future

  • Question about how Oracle manages Redo Log Files

    Good morning,
    Assuming a configuration that consists of 2 redo log groups (Group A and B), each group consisting of 2 disks (Disks A1 & A2 for Group A and Disks B1 and B2 for group B). Further, let's assume that each redo log file resides by itself in a disk storage device and that the device is dedicated to it. Therefore in the above scenario, there are 4 disks, one for each redo log file and, each disk contains nothing else other than a redo log file. Furthermore, let's assume that the database is in ARCHIVELOG mode and that the archive files are stored on yet another different set of devices.
    sort of graphically:
        GROUP A             GROUP B
          A1                  B1
          A2                  B2The question is: When the disks that comprise Group A are filled and Oracle switches to the disks in Group B, can the disks in Group A be taken offline, maybe even physically removed from the system if necessary, without affecting the proper operation of the database ? Can the Archiver process be temporarily delayed until the disks (that were removed) are brought back online or is the DBA forced to wait until the Archiver process has finished creating a copy of the redo log file into the archive ?
    Thank you for your help,
    John.

    Hello,
    Dropping Log Groups
    To drop an online redo log group, you must have the ALTER DATABASE system privilege. Before dropping an online redo log group, consider the following restrictions and precautions:
    * An instance requires at least two groups of online redo log files, regardless of the number of members in the groups. (A group is one or more members.)
    * You can drop an online redo log group only if it is inactive. If you need to drop the current group, first force a log switch to occur.
    * Make sure an online redo log group is archived (if archiving is enabled) before dropping it. To see whether this has happened, use the V$LOG view.
    SELECT GROUP#, ARCHIVED, STATUS FROM V$LOG;
    GROUP# ARC STATUS
    1 YES ACTIVE
    2 NO CURRENT
    3 YES INACTIVE
    4 YES INACTIVE
    Drop an online redo log group with the SQL statement ALTER DATABASE with the DROP LOGFILE clause.
    The following statement drops redo log group number 3:
    ALTER DATABASE DROP LOGFILE GROUP 3;
    When an online redo log group is dropped from the database, and you are not using the Oracle Managed Files feature, the operating system files are not deleted from disk. Rather, the control files of the associated database are updated to drop the members of the group from the database structure. After dropping an online redo log group, make sure that the drop completed successfully, and then use the appropriate operating system command to delete the dropped online redo log files.
    When using Oracle-managed files, the cleanup of operating systems files is done automatically for you.
    Your Database wont be affected as you can operate with 2 redo log files in each group as The minimum number of redo log files required in a database is two because the LGWR (log writer) process writes to the redo log files in a circular manner. so the process will hang becuase you are having 2 only groups if you want to remove 1 add a third one and make it the current group then remove the one you want to be offline.
    Please refer to:
    http://download.oracle.com/docs/cd/B10500_01/server.920/a96521/onlineredo.htm#7438
    Kind regards
    Mohamed
    Oracle DBA

  • How to reduce excessive redo log generation in Oracle 10G

    Hi All,
    Please let me know is there any way to reduce excessive redo log generation in Oracle DB 10.2.0.3
    previously per day there is only 15 Archive log files are generating but now a days it is increased to 40 to 45
    below is the size of redo log file members:
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    Tue Jul 13 14:46:38 2010
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    Thread 1 advanced to log sequence 17440
    Current log# 1 seq# 17440 mem# 0: /u05/applprod/prdnlog/redolog1a.dbf
    Current log# 1 seq# 17440 mem# 1: /u06/applprod/prdnlog/redolog1b.dbf
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    Completed checkpoint up to RBA [0x4420.2.10], SCN: 4871846489
    Tue Jul 13 14:53:33 2010
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    Thread 1 advanced to log sequence 17441
    Current log# 2 seq# 17441 mem# 0: /u05/applprod/prdnlog/redolog2a.dbf
    Current log# 2 seq# 17441 mem# 1: /u06/applprod/prdnlog/redolog2b.dbf
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    Tue Jul 13 15:15:37 2010
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    Tue Jul 13 15:55:39 2010
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    Tue Jul 13 16:35:41 2010
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    Thread 1 advanced to log sequence 17442
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    L
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