ALTER DATABSE FORCE LOGGING

hi,
while creating standby database why should we start the database in force logging mode? what the use of it? what does it do?
With Regards
Boo

Synchorinization between primary and secondary database is done through archive logs. It would be safe to force primary database to log everything, so that it reflects to secondary database. That is the reason we have to force logging.

Similar Messages

Physical standby without ALTER DATABASE FORCE LOGGING

Hi,
Is it possible to use physical standby database without executing ALTER DATABASE FORCE LOGGING on primary side?
Can I use alter tablespace force logginng instead?
I want to have one tablespace with nologging option turned on to reduce redo traffic for some operations.
I can not check this because I don`t have enough servers to build standby configuration.

YuriAP wrote:
Hi,
Is it possible to use physical standby database without executing ALTER DATABASE FORCE LOGGING on primary side?
YES
Can I use alter tablespace force logginng instead?
YES
ALTER TABLESPACE <tablespace name> FORCE LOGGING;
I want to have one tablespace with nologging option turned on to reduce redo traffic for some operations.
I can not check this because I don`t have enough servers to build standby configuration.http://download.oracle.com/docs/cd/B10500_01/server.920/a96521/create.htm#1022863

ORA-02231 error when issue ALTER DATABASE FORCE LOGGING

Hi,
Does everybody know why I faced ORA-02231 when issue below command in oracle,
SQL> ALTER DATABASE FORCE LOGGING;
ALTER DATABASE FORCE LOGGING
ERROR at line 1:
ORA-02231: missing or invalid option to ALTER DATABASE
SQL> ALTER DATABASE FORCE LOGGING ;
ALTER DATABASE FORCE LOGGING
ERROR at line 1:
ORA-02231: missing or invalid option to ALTER DATABASE
SQL> ALTER DATABASE FORCE LOGGING
2
SQL> ALTER TABLESPACE BIIS FORCE LOGGING
2 ;
ALTER TABLESPACE BIIS FORCE LOGGING
ERROR at line 1:
ORA-02142: missing or invalid ALTER TABLESPACE option
I use this oracle version:
Oracle9i Enterprise Edition Release 9.0.1.1.1 - Production
PL/SQL Release 9.0.1.1.1 - Production
CORE 9.0.1.1.1 Production
TNS for 32-bit Windows: Version 9.0.1.1.0 - Production
NLSRTL Version 9.0.1.1.1 - Production
Thanks.

Hi Jaffar,
After I checked that you are correct.
I can issue the command without problem in oracle 9i Rel.2.
Thanks for your information.
Tarman.

Ora-02331 error - while trying to force logging

Hi friends,
i am trying to configure the physical standby database and i am following this documentation http://download.oracle.com/docs/cd/B19306_01/server.102/b14239/create_ps.htm.
when i am trying to do the force logging i am getting the following error.
SQL> alter database force logging;
alter database force logging
ERROR at line 1:
ORA-02231: missing or invalid option to ALTER DATABASE
Can anyone please tell me why it's happening?
Thanks

Which database are you doing this on? Supposed to run
it on the primary. I have only one database i.e primary db and trying to set up physical standby db.
Plus, which version of Oracle? I
see what the document link uses, but that doesn't
mean it is the version you are using.
SQL> select * from v$version;
BANNER
Oracle9i Enterprise Edition Release 9.0.1.1.1 - Production
PL/SQL Release 9.0.1.1.1 - Production
CORE 9.0.1.1.1 Production
TNS for 32-bit Windows: Version 9.0.1.1.0 - Production
NLSRTL Version 9.0.1.1.1 - Production
Can you pls guide me the right way to proceed furthur.

Not dose Force logging.

Hi,
i am trying to create physical standby database.while giving command 'ALTER DATABASE FORCE LOGGING' it gives error like missing or invalid option to alter database.
Pls help.

Hi,
Pls find the output.
SQL> select * from v$version;
BANNER
Oracle9i Enterprise Edition Release 9.0.1.1.1 - Production
PL/SQL Release 9.0.1.1.1 - Production
CORE 9.0.1.1.1 Production
TNS for 32-bit Windows: Version 9.0.1.1.0 - Production
NLSRTL Version 9.0.1.1.1 - Production
SQL> alter database force logging;
alter database force logging
ERROR at line 1:
ORA-02231: missing or invalid option to ALTER DATABASE
SQL>

Question about ALTER SYSTEM ARCHIVE LOG START

Good morning,
I'm trying (unsuccessfully) to get my database to be in archive log mode.
These are the steps I followed:
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount;
ORACLE instance started.
Total System Global Area 535662592 bytes
Fixed Size                  1375792 bytes
Variable Size             377487824 bytes
Database Buffers          150994944 bytes
Redo Buffers                5804032 bytes
Database mounted.
SQL> select log_mode from v$database;
LOG_MODE
ARCHIVELOG
SQL> show parameter log_archive_start;
NAME                                 TYPE        VALUE
log_archive_start                    boolean     FALSE
SQL> alter system archive log start;
System altered.
SQL> show parameter log_archive_start;
NAME                                 TYPE        VALUE
log_archive_start                    boolean     FALSE
SQL>I've gone thru that process twice but, I don't seem to be able to get the ARCH process to start. (newbie mistake I'm sure...)
Thank you for your help (again!),
John.

The parameter log_archive_start is no more needed John (as suggested already) and the best way to check the archive options is through the archive log list command.
[oracle@edhdr2p0-orcl oui]$ sqlplus / as sysdba
SQL*Plus: Release 11.2.0.1.0 Production on Tue Aug 10 10:51:57 2010
Copyright (c) 1982, 2009, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production
With the Partitioning, Automatic Storage Management, OLAP, Data Mining
and Real Application Testing options
SQL> archive log list
Database log mode              No Archive Mode
Automatic archival             Disabled
Archive destination            USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence     11
Current log sequence           13
SQL> shut immediate
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount
ORACLE instance started.
Total System Global Area 418484224 bytes
Fixed Size                  1336932 bytes
Variable Size             318769564 bytes
Database Buffers           92274688 bytes
Redo Buffers                6103040 bytes
Database mounted.
SQL> select process,status from V$archive_processes;
   PROCESS STATUS
         0 STOPPED
         1 STOPPED
         2 STOPPED
         3 STOPPED
         4 STOPPED
         5 STOPPED
         6 STOPPED
         7 STOPPED
         8 STOPPED
         9 STOPPED
        10 STOPPED
   PROCESS STATUS
        11 STOPPED
        12 STOPPED
        13 STOPPED
        14 STOPPED
        15 STOPPED
        16 STOPPED
        17 STOPPED
        18 STOPPED
        19 STOPPED
        20 STOPPED
        21 STOPPED
   PROCESS STATUS
        22 STOPPED
        23 STOPPED
        24 STOPPED
        25 STOPPED
        26 STOPPED
        27 STOPPED
        28 STOPPED
        29 STOPPED
30 rows selected.
SQL>
SQL> alter database archivelog;
Database altered.
SQL> alter database open;
archive log list;
Database altered.
SQL> Database log mode         Archive Mode
Automatic archival             Enabled
Archive destination            USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence     11
Next log sequence to archive   13
Current log sequence           13
SQL>
SQL> select * from V$archive_processes where status <> 'STOPPED';
   PROCESS STATUS     LOG_SEQUENCE STAT
         0 ACTIVE                0 IDLE
         1 ACTIVE                0 IDLE
         2 ACTIVE                0 IDLE
         3 ACTIVE                0 IDLEHTH
Aman....

Advantage of FORCE LOGGING over NOLOGGING

Hi,
Can you please help me on the advantages of using force logging mode with a standby database and the effect of it in indexes etc. Also, it may help if you could also share ideas on difference between the two modes?
Thanks,
Jennah

<i>>> Can you help me what factors would be sacrificed</i>
This really depends on your system, in most cases you will not be able to see a difference. However i did a small test:
- drop index, restart db
- create index with logging (measure time/redo size)
- drop index, restart db
- create index with logging (measure time/redo size)
Result:
logging - Elapsed: 00:02:40.68 / Redo size: 800mb
nologging - Elapsed: 00:02:20.29 / Redo size: 1.5mb
Here the full test:
[code]SQL> select a.name, b.value from v$statname a, v$mystat b where a.statistic# = b.statistic# and a.name = 'redo size';
NAME                                                                  VALUE
redo size                                                             28304
SQL> CREATE UNIQUE INDEX "SAPR3"."CDCLS~0" ON "SAPR3"."CDCLS"
("MANDANT", "OBJECTCLAS", "OBJECTID", "CHANGENR", "PAGENO")
PCTFREE 10 INITRANS 2 MAXTRANS 255
STORAGE(INITIAL 65536 NEXT 65536 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT)
TABLESPACE "PSAPCLUI" LOGGING;
Index created.
Elapsed: 00:02:40.68
SQL> select a.name, b.value from v$statname a, v$mystat b where a.statistic# = b.statistic# and a.name = 'redo size';
NAME                                                                  VALUE
redo size                                                         834714816
SQL> select segment_name, bytes/1024/1024 "Size_MB" from dba_segments where segment_name = 'CDCLS~0'
SEGMENT_NAME            Size_MB
CDCLS~0                     800
drop index / db restart here
SQL> select a.name, b.value from v$statname a, v$mystat b where a.statistic# = b.statistic# and a.name = 'redo size';
NAME                                                                  VALUE
redo size                                                             28992
SQL> CREATE UNIQUE INDEX "SAPR3"."CDCLS~0" ON "SAPR3"."CDCLS"
("MANDANT", "OBJECTCLAS", "OBJECTID", "CHANGENR", "PAGENO")
PCTFREE 10 INITRANS 2 MAXTRANS 255
STORAGE(INITIAL 65536 NEXT 65536 MINEXTENTS 1 MAXEXTENTS 2147483645
PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT)
TABLESPACE "PSAPCLUI" NOLOGGING;
Index created.
Elapsed: 00:02:20.29
SQL> select a.name, b.value from v$statname a, v$mystat b where a.statistic# = b.statistic# and a.name = 'redo size';
NAME                                                                  VALUE
redo size                                                           1520824
SQL> select segment_name, bytes/1024/1024 "Size_MB" from dba_segments where segment_name = 'CDCLS~0';
SEGMENT_NAME            Size_MB
CDCLS~0                     800[/code]

FORCE LOGGING

I want to create a physical standby database. The primary database is in archive log mode, and the 50% of the data belong to the staging area of datawarehouse. During ETL processes the database generates great amount of GBs of redologs. This tables contain temporary data that are only used for ETL process.
Can I set the database like FORCE LOGGING=N and set FORCE LOGGING=Y only for the tablespace that contain the tables of data (production, not intermediate) ???

If you are trying to run a physical standby, for any database larger and more important than a toy, across the internet you are doomed to failure.
Databases do not fail on predictable schedules.
A DR site means a DR site ... it does not mean someplace out there in the cloud. For all you know your redo is being shipped to the moon and
back. Buy room in a data center no more than 500km away from your current location.
DR is for serious people with serious issues. If you do not need it then don't build it. If you do need it build it correctly.

Force logging in archivelog mode

Hi !!!
What happen if I have "force_logging" parameter set to true when the database is in archivelog mode ?
Thanks.

rarain wrote:
Hi Juamd,
You should only use this option when it is really required because this option will forcibly generate redo for all Nologging operations that means you might find more archives and you need to setup more space for archive.
Normally we use this option when we need to replicate data changes from one database to another database like in standby configuration, Golden Gate replication etc. I would suggest you to monitor Redo amount generated after enabling this option and accordingly estimate archive space and backup space for archive.
Thanks...Ah, don't agree with that at all. You can compromise your recovery if you happen to want to restore to a point-in-time when there was a NOLOGGING operation going on. Fine, if it's an index, but if it happens to be on a table...
(Yes, been there, done that - with a non-Production database, thankfully)
This is one of the 'must haves', IMO, for Production - set it at the database-level and it overrides any tablespace or object setting.
Archivelogs are generated for a reason. If you have a particular operation that really does massively benefit from NOLOGGING and is something you are sure that you simply re-run/re-create yourself, fine. If not, by default, you really should FORCE LOGGING.

Alter system archive log current

Hi everyone,
I write code to alter system archive log current in PL/SQL as following:
declare
start_sequence number;
end_sequence number;
begin
--- get start sequence# ---
select SEQUENCE# into start_sequence from v_$log where status='CURRENT';
--- get end sequence# ---
alter system archive log current;
select SEQUENCE# into end_sequence from v_$log where status='CURRENT';
end;
When I run it, I got the following error:
alter system archive log current;
ERROR at line 11:
ORA-06550: line 11, column 6:
PLS-00103: Encountered the symbol "ALTER" when expecting one of the following:
begin case declare end exception exit for goto if loop mod
null pragma raise return select update while with
<an identifier> <a double-quoted delimited-identifier>
<a bind variable> << close current delete fetch lock insert
open rollback savepoint set sql execute commit forall merge
pipe
What does it mean? How can I fix it/
Thanks!

That is because you are trying to issue a DDL call in PL/SQL. The only way you can achieve this is to use DYNAMIC SQL.
If you change your ALTER statement to:
EXECUTE IMMEDIATE 'ALTER SYSTEM ARCHIVE LOG CURRENT';It should work.
HTH!

RMAN ALert Log Message: ALTER SYSTEM ARCHIVE LOG

Created a new Database on Oracle 10.2.0.4 and now seeing "ALTER SYSTEM ARCHIVE LOG" in the Alert Log only when the online RMAN backup runs:
Wed Aug 26 21:52:03 2009
ALTER SYSTEM ARCHIVE LOG
Wed Aug 26 21:52:03 2009
Thread 1 advanced to log sequence 35 (LGWR switch)
Current log# 2 seq# 35 mem# 0: /u01/app/oracle/oradata/aatest/redo02.log
Current log# 2 seq# 35 mem# 1: /u03/oradata/aatest/redo02a.log
Wed Aug 26 21:53:37 2009
ALTER SYSTEM ARCHIVE LOG
Wed Aug 26 21:53:37 2009
Thread 1 advanced to log sequence 36 (LGWR switch)
Current log# 3 seq# 36 mem# 0: /u01/app/oracle/oradata/aatest/redo03.log
Current log# 3 seq# 36 mem# 1: /u03/oradata/aatest/redo03a.log
Wed Aug 26 21:53:40 2009
Starting control autobackup
Control autobackup written to DISK device
handle '/u03/exports/backups/aatest/c-2538018370-20090826-00'
I am not issuing a log swiitch command. The RMAN commands I am running are:
CONFIGURE RETENTION POLICY TO REDUNDANCY 2;
CONFIGURE CONTROLFILE AUTOBACKUP ON;
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '/u03/exports/backups/aatest/%F';
CONFIGURE DEVICE TYPE DISK BACKUP TYPE TO COMPRESSED BACKUPSET;
CONFIGURE CHANNEL DEVICE TYPE DISK FORMAT '/u03/exports/backups/aatest/%d_%U';
BACKUP DATABASE PLUS ARCHIVELOG;
DELETE NOPROMPT OBSOLETE;
DELETE NOPROMPT ARCHIVELOG UNTIL TIME 'SYSDATE-2';
I do not see this message on any other 10.2.0.4 instances. Has anyone seen this and if so why is this showing in the log?
Thank you,
Curt Swartzlander

There's no problem with log switch. Please refer to documentation for more information on syntax "PLUS ARCHIVELOG"
http://download.oracle.com/docs/cd/B19306_01/backup.102/b14192/bkup003.htm#sthref377
Adding BACKUP ... PLUS ARCHIVELOG causes RMAN to do the following:
*1. Runs the ALTER SYSTEM ARCHIVE LOG CURRENT command.*
*2. Runs BACKUP ARCHIVELOG ALL. Note that if backup optimization is enabled, then RMAN skips logs that it has already backed up to the specified device.*
*3. Backs up the rest of the files specified in BACKUP command.*
*4. Runs the ALTER SYSTEM ARCHIVE LOG CURRENT command.*
*5. Backs up any remaining archived logs generated during the backup.*
This guarantees that datafile backups taken during the command are recoverable to a consistent state.

Direct Path Loads Vs FORCED LOGGING

Hello everyone,
I just got below doubt.
Suppose, we've
One Oracle Primary Database (running in FORCED LOGGING mode) and,
One Oracle Standy Database (Oracle Data Gaurd)
My doubt is that if we use sqlloader direct path to load data in a table in primary database, will it generate/send the redo and ship the same to standby database ?

Thanks Anil,
But have a doubt again.
How does direct path data upload generate redo if it's working on just data blocks.
I.e. get the block adjust the high water and put the records.

Sql query needed to verify force logging

Hi.
Does anyone out there have SQL query we need to run in order to see if our db is working in force logging mode?
Thanks.
DA

The FORCE_LOGGING column of v$database view can be queried to verify that the database is in FORCE LOGGING mode. Similarly, the FORCE_LOGGING column of dba_tablespace view provides the same information for each tablespace.
Kamran Agayev A. (10g OCP)
http://kamranagayev.wordpress.com

Force logging at tablespace level for standby database

Hi
Can we create a standby database by enabling force logging at tablespace level instead of enabling it at database level.I want to out the tablespace containing indexes in nologging mode so that when I rebuild the indexes no logs will be generated.

Technically, you can create a Standby without having set FORCELOGGING at the Primary database.
You can also then selectively FORCELOGGING for all your important tablespaces (beginning with SYSTEM, SYSAUX, UNDO ....)
However, for a Physical Standby Redo Apply will mark the blocks (e.g. those populated by the CREATE INDEX .. NOLOGGING) as "corrupt". You will get Read Errors (ORA-1578 and ORA-26040) when you attempt to read the index (e.g. for a Table query).
So you have to monitor your NOLOGGING operations and the datafiles where NOLOGGING is applied. You can take Incremental RMAN Backups of such datafiles and restore them to the Standby immediately after the NOLOGGING operations.
Hemant K Chitale

What is 'force logging'?

Why we need some ddl not to be wroten to the redo logs? What is the idea? How can we recover the database if some infromation in archivelogs is missed?
Thanks in advance

In theory, yo may wish to allow an application to load data as a "no logging" operation, this can speed up large data loads and reduce the volume of archivelogs produced.
However the major drawbacks are:
if you need to recover the database form a backup any data added using a no logging operation performed after the backup was taken will not be recoverable from the archive logs.
If you are using log shipping/data guard these operations will not get transmitted to the standby server.
If you work in a controlled an disciplined enviroment then it should be possible to repeat any no logging operations after the database is recovered as everyone should be aware of the limitations of loading data in this manner.
If you work anywhere thats like the places I've come accross a more likely situation is after a database recovery someone will want to know why data is missing from the database and how long it will be untill you resolve the problem. Usually I set force logging on and let the users think they have the option to run nologgign operations as it leads to a quieter life in the long run.

ALTER DATABSE FORCE LOGGING

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