Maxdb log mode

hello experts,
      I need to change the log mode which is in "overwrite mode"
    currently. and increase LOG_IO_QUEUE size.
   how can i do it.
   our maxdb version is 7.6 and O/S linux 2.6.16
   plz suggest steps .
thanks and regards

Dear Kavitha,
-> Please review the SAP notes::
                869267        FAQ: MaxDB LOG area
     < "35. Can the log area be overwritten cyclically without having to make a log backup?"
        "52. How large should the LOG_IO_QUEUE be when configured? " >
             719652     Setting initial parameters for liveCache 7.5 or 7.6
             819641     FAQ: MaxDB Performance
     If you are SAP customer, you are able to read the SAP notes.
-> The MAXDB documentation also give you answers on the reported questions::
            http://maxdb.sap.com/documentation/ -> Open the SAP MaxDB 7.6 Library
             -> Glossary
          "Changing the Values of Database Parameters" at
                  http://maxdb.sap.com/doc/7_6/9b/e6dc41765b6024e10000000a1550b0/content.htm
          "Log Queue"
                http://maxdb.sap.com/doc/7_6/23/c806c81e20f946a59a421e01c42c3b/content.htm
         < The new value of the LOG_IO_QUEUE parameter will be activated only after
            the database will be restarted from offline mode. >
          "Displaying and Changing Database Parameters" using DBMGUI tool at
                http://maxdb.sap.com/doc/7_6/84/d8d198570411d4aa82006094b92fad/content.htm
-> Please pay attention ::
      "Automatic overwrite of the log area without log backups is NOT
           recommended for production operation. Since no backup history exists
           for the following changes in the database, you cannot track transactions
           in the case of recovery. "
      Run dbm command 'param_getexplain LOG_IO_QUEUE'.
          May be the log devspaces can be moved to a faster disk, to accelerate the physical log I/O.
-> What is the version of the database? < Please also give the patch and build number >
     Why do you need to change the log mode which is in "overwrite mode"
      and increase the value of the database parameter LOG_IO_QUEUE?
Thank you and best regards, Natalia Khlopina

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Steps to empty SAPDB (MaxDB) log file

Hello All,
i am on Redhat Unix Os with NW 7.1 CE and SAPDB as Back end. I am trying to login but my log file is full. Ii want to empty log file but i havn't done any data backup yet. Can anybody guide me how toproceed to handle this problem.
I do have some idea what to do like the steps below
1. take databackup (but i want to skip this step if possible) since this is a QA system and we are not a production company.
2. Take log backup using same methos as data backup but with Log type (am i right or there is somethign else)
3. It will automatically overwrite log after log backups.
or should i use this as an alternative, i found this in note Note 869267 - FAQ: SAP MaxDB LOG area
Can the log area be overwritten cyclically without having to make a log backup?
Yes, the log area can be automatically overwritten without log backups. Use the DBM command
util_execute SET LOG AUTO OVERWRITE ON
to set this status. The behavior of the database corresponds to the DEMO log mode in older versions. With version 7.4.03 and above, this behavior can be set online.
Log backups are not possible after switching on automatic overwrite. Backup history is broken down and flagged by the abbreviation HISTLOST in the backup history (dbm.knl file). The backup history is restarted when you switch off automatic overwrite without log backups using the command
util_execute SET LOG AUTO OVERWRITE OFF
and by creating a complete data backup in the ADMIN or ONLINE status.
Automatic overwrite of the log area without log backups is NOT suitable for production operation. Since no backup history exists for the following changes in the database, you cannot track transactions in the case of recovery.
any reply will be highly appreciated.
Thanks
Mani

Hello Mani,
1. Please review the document u201CUsing SAP MaxDB X Server Behind a Firewallu201D at MAXDB library
http://maxdb.sap.com/doc/7_7/44/bbddac91407006e10000000a155369/content.htm
u201CTo enable access to X Server (and thus the database) behind a firewall using a client program such as Database Studio, open the necessary ports in your firewall and restrict access to these ports to only those computers that need to access the database.u201D
Is the database server behind a Firewall? If yes, then the Xserver port need to be open. You could restrict access to this port to the computers of your database administrators, for example.
Is "nq2host" the name of the database server? Could you ping to the server "nq2host" from your machine?
2. And if the database server and your PC in the local area NetWork you could start the x_server on the database server & connect to the database using the DB studio on your PC, as you already told by Lars.
See the document u201CNetwork Communicationu201D at
http://maxdb.sap.com/doc/7_7/44/d7c3e72e6338d3e10000000a1553f7/content.htm
Thank you and best regards, Natalia Khlopina

Standby Database (Archive Log Mode)

I'm going to be setting up a standby database.
I understand that the primary database must be in archive log mode.
Is there any reason for the standby database to be in archivelog mode?

Since your primary Db is in archive log mode, so will be your standby, when it is made primary.But. you can use STANDBY REDO LOGS from 9i version, where these Standby Redo Logs then store the information received from the Primary Database.
As per metalink:-
>
Standby Redo Logs are only supported for the Physical Standby Database in Oracle 9i and as well for Logical Standby Databases in 10g. Standby Redo Logs are only used if you have the LGWR activated for archival to the Remote Standby Database.If you have Standby Redo Logs, the RFS process will write into the Standby RedoLog as mentioned above and when a log switch occurs, the Archiver Process of the Standby Database will archive this Standby Redo Log to an Archived Redo Log, while the MRP process applies the information to the Standby Database. In a Failover situation, you will also have access to the information already written in the Standby Redo Logs, so the information will not be lost.
>
Check metalink Doc ID: Note:219344.1
Regards,
Anand

Is the only way to import large amount of data and database objects into a primary database is to shutdown the standby, turn off archive log mode, do the import, then rebuild the standby?

I have a primary database that need to import large amount of data and database objects. 1.) Do I shutdown the standby? 2.) Turn off archive log mode? 3.) Perform the import? 4.) Rebuild the standby? or is there a better way or best practice?

Instead of rebuilding the (whole) standby, you take an incremental (from SCN) backup from the Primary and restore it on the Standby. That way, if, for example
a. Only two out of 12 tablespaces are affected by the import, the incremental backup would effectively be only the blocks changed in those two tablespaces (and some other changes in system and undo) {provided that there are no other changes in the other ten tablespaces}
b. if the size of the import is only 15% of the database, the incremental backup to restore to the standby is small
Hemant K Chitale

SAP DB changing the Log mode to the "Owerwrite mode is ON"

Hi!
I would like to know, which consequences do I have, changing the Log mode to the "Owerwrite mode is ON".
Is that comparable with Oracle's archive mode?
What should I note proccessing so (e.g. to make back up)
I don't use the system in productive mode and would like to save/spare free space on my server....
Thank you very much!
regards
Axel

Hi Marcus,
once again to clarify: I know it from oracle: Is it right that , If I activate in SAP DB "Owerwrite mode is. ON" no new logfiles will be created.
Only the existing logfiles will be overwrtiten.
It means I "save" space, because no new log files a 4,5 GB will be created, is not?
I am not familiar with SAP DB.
How should I proceed with Backup (online, offlne)?
Thank you
regards

Question about import in archive log mode

Hello.
I am a developer, I have ordered to write a script that makes the import of a schema of a database (release 9.2.0.7). That import will be done once a day. I have seen that in my development environment the import creates 54 archivers files (10M aprox. each), that means more that half a Gb a day, it seems too much to me.
I cannot see why all those archivers can be useful. Would a good way of proceeding the following?
1. Forcing an archiver just before the import (I do not know how to do that) so that a backup could be done to the state before the import.
2. Disabling archive log mode during the import and enabling it just after the import (I do not know how to do that).
3. Forcing a new archiver just after the import (I do not know how to do that).
Thanks in advance.

540M is not that much.
One would question why you need to import every day,
there must be better ways to do this.
The three steps you propose look like an awful
scenario, as it would require the database to switch
from archivelog to noarchivelog and vice versa.
This would require the database to close twice a
day.
The scenario is also incomplete as one would need to
take a backup after the import
If you can convince your DBA to close the database
twice a day, he should write the script, which he can
easily derive from the docs.
But likely he will visit Billy Verreynne to borrow
his lead pipe, and rightly so ;)
Sybrand Bakker
Senior Oracle DBAThanks for the answer.
A few things:
- Sorry for my ignorance, I have no experience in database backups, I do not understand why I need to backup just after the import.
- That database is not critical, it is just for a team who will test on that database several applications, so the database will only need to be open during the office schedule.
- I have no dba. The client has a dba for several databases but I have no contact with him/her nor my boss has.

Archive log mode in oracle 10g

Hi,
I would like to know the archive log mode in oracle 10g and I use this code in SQLPlus
select log_mode from v$database
But it displayed: "2" not : NOARCHIVELOG or ARCHIVELOG
It displayed a number, not a String.
How could I know this?
Thanks

Hi Paul
Because I am a newbie in DBA Oracle so I got many difficulties.
You are very kind to help me.
So I have some more questions:
1. when I executed this code, it always reported error:
$ tmp=`${ORACLE_HOME}/bin/sqlplus -s / as sysdba << EOF
set heading off feedback off;
exit
EOF`
tmp='ERROR:
ORA-01031: insufficient privileges
SP2-0306: Invalid option.
Usage: CONN[ECT] [logon] [AS {SYSDBA|SYSOPER}]
where <logon> ::= <username>[<password>][@<connect_identifier>] | /
SP2-0306: Invalid option.
Usage: CONN[ECT] [logon] [AS {SYSDBA|SYSOPER}]
where <logon> ::= <username>[<password>][@<connect_identifier>] | /
SP2-0157: unable to CONNECT to ORACLE after 3 attempts, exiting SQL*Plus'
so when I updated like this:
tmp=`${ORACLE_HOME}/bin/sqlplus -s sys/syspass@db02 as sysdba <<EOF
               set heading off feedback off;
               exit
               EOF`
It run correctly.
2. With Paul's guide:
Do not execute Oracle commands from root, execute them as oracle user. This works to me :
$ tmp=`${ORACLE_HOME}/bin/sqlplus -s / as sysdba << EOF
set heading off feedback off
alter database backup controlfile to '${CONTROLFILE_DIR}/<file name>';
alter database backup controlfile to trace;
exit
EOF`
Of course CONTROLFILE_DIR must be set to a directory with write permission for oracle user.
For ex: I have an Unix account: unix/unix
and a Sys Oracle account: oracle/oracle
I login with Unix acount (unix/unix) and call script file that contains above code.
tmp=`${ORACLE_HOME}/bin/sqlplus -s oracle/oracle@db02 as sysdba <<EOF
               set heading off feedback off
               alter database backup controlfile to '${CONTROLFILE_DIR}/backup_control.ctl';
               alter database backup controlfile to trace;
               exit
               EOF`
Unix report as following: Linux error: 13: Permission denied.
CONTROLFILE_DIR directory is read,write,execute for account unix/unix.
Of course CONTROLFILE_DIR must be set to a directory with write permission for oracle user. You mean I have to create a Unix user is the same to Oracle user so that Oracle user can have permission to write.
Please guilde more detail.
Thanks for your attention.
Message was edited by:
user481034

Disabling Log_Archive_Start in Archive Log Mode

Guys,
I have a Database running in Archive Log mode.
I have a situation where in I have to do bunch of bulk updates for which I dont want any logs generated.
sO I was thinking to set the intialization parameter log_archive_start to false before I run the DML updates
ALTER SYSTEM SET log_archive_start = false
after the DML is run I will turn it back on
ALTER SYSTEM SET log_archive_start = True
Do you think if this is the right to go about or would I have to switch from Archive Log Mode to No Archive Log Mode
run the DML update and then switch back to Archive Log Mode
Any comments/suggestions/inputs woo

Hello,
I would use some other way to get a full nologing behaviour.
First, ensure your tablespace is in force logging mode.
ALTER TABLESPACE data FORCE LOGGING NOLOGGING;
ALTER TABLESPACE index FORCE LOGGING NOLOGGING;
This will ensure that you're usually logging.
Set all tables/indexes to be nologging
BEGIN
FOR vRes IN (SELECT OWNER,TABLE_NAME FROM DBA_TABLES WHERE TABLESPACE_NAME='data')
LOOP
EXECUTE IMMEDIATE 'ALTER TABLE ' || vRes.OWNER || '.' || vRes.TABLE_NAME ' NOLOGGING';
END LOOP;
END;
Do even for indexes.
From now on, when you want to do your huge amount of updates/... targetting objects in tablespaces data and index, jou just have to:
ALTER TABLESPACE data NO FORCE LOGGING;
ALTER TABLESPACE indexes NO FORCE LOGGING;
- Your DML
ALTER TABLESPACE data FORCE LOGGING;
ALTER TABLESPACE indexes FORCE LOGGING.
4 commands to disable logging for every object in the tablespace.
Beware, when in NOLOGGING mode, you won't be able to "RECOVER" any of the tables. Thiis is not crash-friendly, but you'll have no redo info generated, which is what you require.
Regards,
Yoann.

Physical standby in archive log mode

HI ,
Our phyiscal standby database is running in archive log mode,
1.Is it manadatory to have it in archive log mode ?
2.As it is in archive log mode , does it produce any archivelog ?

Hello again;
The Standby is a clone of the Primary. I assume we are talking Physical Standby.
Why does it need to produce archive in standby role?Its does not produce archive in the Standby role. I have seen a Standby produce a log now and then, but not log after log like a primary. A Standby database does not write Redo or use Redo logs, it uses Standby Redo logs. Since Redo logs are not used, archive is not written.
Why it is manadatory to enable archive log in standby?Smart design I'm thinking. Why would Oracle make us add this complex step to a failover/switchover?
Keep it simple if possible.
Data Guard Concepts and Administration 11g Release 2 (11.2) E10700-02
Database Concepts
http://docs.oracle.com/cd/E11882_01/server.112/e25789/process.htm
Best Regards
mseberg

Archive log mode

Hi
i m using oracle 10gR2 after installation i enable the archive log mode.
1) How can i determine the size of archive log?
2)When i enable the archive log mode after switch it genrate the second archive (01_MF_1_2_43.ARC) instead of first (01_MF_1_1_43.ARC) why?
Thanks

The size of archived logs will normally be the same as the size of online redo logs. However, if you switch the logs before the get filled with redo, the size of archived log will be smaller depending in the amount of redo.

Archive log mode Turn off

Hi all DBA guys, Have a Nice day all
If i change archive log mode to no archive log mode, internally whats happen my database?.
Is this old archive log backup use for future if again convert no archive to archive log mode?
What's happen flashback if i change archive log mode to no archive log mode?
Regards
S.Azar

azarmohds wrote:
Thanx lot,
why i asked this question means, rightnow you posted, this is feature of 10g i.e flashback database confiured when archive log mode is enabled...,so in this case
What's happen flashback if i change archive log mode to no archive log mode?S.Azar,
You should be clear about things that when you read notes from web, there can be a language mismatch. So the best is that search first over the oracle docs.
Now about your doubt, its a terminology mismatch which is happening here. To enable Flashback Database feature which is more persistent copy of the undo data , stored seperately in a FLB file, you MUST have to have archivelog mode configured in your db. Without this, you can't enable the Flashback Database feature. And you can't switch to noarchive log mode as well if you have Flashback Database mode on.
The other thing ( which I guess Anurag was mentioning ) is the normal Flashback feature which relies on Undo data stored in the undo tablespace. This solely is based on teh undo data and doesn't depend on the archive/nonarchive log mode of the database. But this is limited to that data and to that time period up till which you can store the undo data in your undo tablespace.
HTH
Aman....

Archive log mode doubt

Hi All,
We have 10g R2 database running on RHEL 4 OS. In order to set the archive log mode for the database, if we set only log_archive_dest_n parameter is only enough or we have to set db_recovery_file_dest_size and db_recovery_file_dest also? i know that these 2 parameters are required to configure the flash_recovery_area. my doubt is whether, do we need to set flash_recovery_area parameters and log_archive_dest_n parameters to take backup of databases or set only the log_archive_dest_n parameter and enable archive log mode and take backup using RMAN?
Thanks,
Praveen.

Hi,
To use RMAN to take a hot backup you need only set LOG_ARCHIVE_DEST_n and place the database in archive log mode. RMAN can be used to backup changed data even after a nologging operation, and you can move away from archivelog mode.
http://www.stanford.edu/dept/itss/docs/oracle/10g/server.101/b10726/configbp.htm
There is also the new "block change tracking" B&R that does not need archivelog mode:
http://www.dba-oracle.com/t_block_change_tracking.htm

Archive log mode in 3 node rac database

Sir I am using oracle 10.2.0.1 and created 3 node cluster setup on.OS i am using linux 4
I am too much confuse in setting up this cluster in archive log mode bec why we need to false cluater_database parameter to setup cluster in archive log mode.
I have search lot of documents but all are saying we not need setting this parameter flase perior to 10.2.But what is the actual concept behind setting this parameter to false in early release and why we need not to set it false.Please help me.
I know how to set up in archive log mode but this parameter create confusion.
Thanks sir in advance

I also dont't know all the details about this but I'll try to explain what I know. Setting cluster_database to false in a rac environment is usually done when you need to mount the database from one instance exclusively. This is still needed when you upgrade the catalog, for example during release update (from 10.2.0.1 to 10.2.0.4 for example). Now with switching archivelog mode someone at oracle must have discovered that it is sufficient when the database is mounted by only one instance and you can actually save one step.
As I (and propably most of you) don't switch archiving on or off on a daily basis, I don't worry about this a lot, simply turn this on when I create a new database and then leave it on forever.
Bjoern

SGEN & database archive log mode

Hi Experts,
To apply ABAP support packs, I disabled archive log mode of databse and successfully applied support packs.
As post processing, I kicked off SGEN.
Is it required that database be in "NO Archive log mode" while SGEN is running or can I enable it.
Thanks
Putla

Not sure what database it is.. but if it is ORACLE...
$sqlplus / as sysdba
SQL> shutdown immediate;
SQL> startup mount;
SQL> Alter database noarchivelog;
SQL> alter database open;
After the completion of SGEN.....
$sqlplus / as sysdba
SQL> shutdown immediate;
SQL> alter database mount;
SQL> alter database archivelog;
SQL> alter database open;

RECOVERY IN NOARCHIVE LOG MODE

Dear all,
Please help me in solving this recovery issue :
My database is : oracle 8i server ent.edition
database runs on windows 2000
db confgiured in no archive logmode
when I start the database today :
am getting the following error :
O/S-Error: (OS 23) Data error (cyclic redundancy check).'
error 1242 detected in background process
ORA-01242: data file suffered media failure: database in NOARCHIVELOG mode
ORA-01114: IO error writing block to file 2 (block # 1936)
ORA-01110: data file 2: 'c:\ORACLE\ORADATA\ORACLE\RBS01.DBF'
ORA-27072: skgfdisp: I/O error
OSD-04008: WriteFile() failure, unable to write to file
O/S-Error: (OS 23) Data error (cyclic redundancy check).
this tablespace rbs is defined only for rollback segments..
since db in noarhicve log mode, I cant able to take the datafile offline.. I tried doing
ALTER DATABASE RECOVER
which resulted in the above error .
I have valid 1 month old cold backup..
when I try to drop the tablespace, it fails with the above error.. .
Please guide me as this is the production database..
Thanks in advance
Please help me
Kai

Were you able to achieve a NORMAL or IMMEDIATE shutdown of the database ?
In that case the Rollback segments are not required at startup.
So,
1 comment out the entry "rollback_segments=...(namesofrollbacksegments)"
from the init.ora
2. connect / as sysdba and STARTUP MOUNT;
3. ALTER DATABASE DATAFILE '<filenameforRBS>' OFFLINE DROP ;
4. ALTER DATABASE OPEN;
Additional steps : CREATE ROLLBACK SEGMENT SYS_RBS01
TABLESPACE SYSTEM;
ALTER ROLLBACK SEGMENT SYS_RBS01 ONLINE;
5. DROP TABLESPACE RBS ; (check the name of the tablespace)
6. CREATE TABLESPACE RBS (or NEWRBS) DATAFILE ....
7. CREATE ROLLBACK SEGMENT ........ and create multiple segments in
the new RBS tablespace
8. SHUTDOWN
9. Edit init.ora to set the rollback segment names again
10. STARTUP
HOWEVER if your database shutdown was not normal or immediate but an
abort, Oracle would try to do an Instance Recovery. In that case, you would
need to use "_corrupted_rollback_segments" and may lose data consistency.
Check MetaLink for notes on that. But first check your shutdown and see if
you can follow the steps suggested by Sybrand and me.
Added additional steps for SYS_RBS01 in the SYSTEM
tablespace for any actions on the RBS tablespace.
Message was edited by:
Hemant K Chitale

Maxdb log mode

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