bottleneck during the passage of the redo log files.

Similar Questions

• How do I know if there's bottleneck in the redo logs?

  Hi all

  EBS R12.2

  11 GR 2

  OL 6.5

  We have two groups of log of size 1 GB.

  and oyour archiving logs generates 13 newspapers every hour.

  -rw - r-. 1 oraprod s/n 956896768 Jan 25 14:00 1_3372_898613761.dbf

  -rw - r-. 1 oraprod s/n 1004083200 Jan 25 14:03 1_3373_898613761.dbf

  -rw - r-. 1 oraprod s/n 928530432 Jan 25 14:10 1_3374_898613761.dbf

  -rw - r-. 1 oraprod s/n 928728576 Jan 25 14:12 1_3375_898613761.dbf

  -rw - r-. 1 oraprod s/n 967805952 Jan 25 14:20 1_3376_898613761.dbf

  -rw - r-. 1 oraprod s/n 916065792 Jan 25 14:22 1_3377_898613761.dbf

  -rw - r-. 1 oraprod s/n 951790592 Jan 25 14:30 1_3378_898613761.dbf

  -rw - r-. 1 oraprod s/n 978358272 Jan 25 14:32 1_3379_898613761.dbf

  -rw - r-. 1 oraprod s/n 974519808 Jan 25 14:40 1_3380_898613761.dbf

  -rw - r-. 1 oraprod s/n 960421376 Jan 25 14:42 1_3381_898613761.dbf

  -rw - r-. 1 oraprod s/n 917438976 Jan 25 14:49 1_3382_898613761.dbf

  -rw - r-. 1 oraprod s/n 920794624 Jan 25 14:51 1_3383_898613761.dbf

  -rw - r-. 1 oraprod s/n 920704000 Jan 25 14:59 1_3384_898613761.dbf

  I got this alert saves messages:

  Mon Jan 25 15:08:37 2016

  Filled checkpoint up to RBA [0xd3b.2.10], RCS: 5978324588151

  Mon Jan 25 15:10:57 2016

  Thread 1 cannot allot of new newspapers, sequence 3388

  Private stream flush is not complete

  Currently journal # 1, seq # 3387 mem # 0: /home/oraprod/PROD/data/log01a.dbf

  Currently journal # 1, seq # 3387 mem # 1: /home/oraprod/PROD/data/log01b.dbf

  Beginning log switch checkpoint up to RBA [0xd3c.2.10], RCS: 5978324634623

  Thread 1 Advanced for you connect to sequence 3388 (switch LGWR)

  Currently Journal # 2 seq # 3388 mem # 0: /home/oraprod/PROD/data/log02a.dbf

  Currently Journal # 2 seq # 3388 mem # 1: /home/oraprod/PROD/data/log02b.dbf

  Mon Jan 25 15:11:01 2016

  LNS: Standby redo log file selected for thread 1 sequence 3388 for destination LOG_ARCHIVE_DEST_2

  Mon Jan 25 15:11:04 2016

  Archived journal 6791 extra for each sequence 1 3387 ID thread entry 0 x 12809081 dest 1:

  Mon Jan 25 15:11:17 2016

  Filled checkpoint up to RBA [0xd3c.2.10], RCS: 5978324634623

  Mon Jan 25 15:13 2016

  Additional checkpoint up to RBA to RBA [0xd3c.1a8e82.0] [0xd3c.18d210.0], current journal line

  Mon Jan 25 15:13:04 2016

  Thread 1 cannot allot of new newspapers, sequence 3389

  Private stream flush is not complete

  Currently Journal # 2 seq # 3388 mem # 0: /home/oraprod/PROD/data/log02a.dbf

  Currently Journal # 2 seq # 3388 mem # 1: /home/oraprod/PROD/data/log02b.dbf

  Beginning log switch checkpoint up to RBA [0xd3d.2.10], RCS: 5978324673444

  Thread 1 Advanced for you connect to 3389 (switch LGWR) sequence

  Currently journal # 1, seq # 3389 mem # 0: /home/oraprod/PROD/data/log01a.dbf

  Currently journal # 1, seq # 3389 mem # 1: /home/oraprod/PROD/data/log01b.dbf

  Mon Jan 25 15:13:07 2016

  LNS: Standby redo log file selected for thread 1 sequence 3389 for destination LOG_ARCHIVE_DEST_2

  Mon Jan 25 15:13:09 2016

  Archived journal 6793 extra for each sequence 1 3388 ID thread entry 0 x 12809081 dest 1:

  Mon Jan 25 15:13:11 2016

  Filled checkpoint up to RBA [0xd3d.2.10], RCS: 5978324673444

  Is it a sign of botteneck? Users complained that each 15:00 they encounter performance degradation.

  Kind regards

  JC

  Jenna_C wrote:

  We have two groups of size 1 GB log and our archiving logs generates 13 newspapers every hour.

  Is it a sign of botteneck? Users complained that each 15:00 they encounter performance degradation.

  If your users are complaining about slow at 15:00 then look at what is happening on the system at this point in time.  Use the Active Session history, providing that you have the license, at 3 pm to see if there is a problem.  Or take snapshots of the AWR manually around 15:00 in an attempt to capture any anomaly.  Or capture instant V$ SESSION yourself manually around 15:00 and see so many sessions is pending or not.

  I have seen problems like this on shared physical infrastructure systems where the activity on a system can interfere with each other.  Attention to this kind of thing, because if it is caused by another system then you will never find the cause of the problem inside the Oracle.  Examples include backups are made at a specific time, causing large amounts of sequential disk i/o and slows down access to the drive for everything else.  Such a scenario could cause some writing redo log time to increase significantly.  Or the backup could be another system completely who shares the same disks in the same drive bay or the SAN and Bay drives or SAN is inundated by applications e/s backup.  But as it's another system, that you will not see what is happening on your Oracle database system.

  Or a virtualized with environment sharing CPU and memory where another virtual machine running a CPU intensive job and steals the Oracle system CPU capacity.  I saw the same thing with memory so - Vmware has a strange way to virtualize memory, which means it can use all of the memory on the physical hardware and run out, and then he had to intervene to release somehow little memory.  What ends up slowing things down.

  It could be a network problem - is something that the network of the floods at 15:00?  Still, backups can be a common cause of this, during the transfer of data over the network to another system.  Is there a work extracted regularly data which runs at 15:00 for example extract given OLTP to feed into a data warehouse, which is copied on the network?

  It could be many different things, causing the slowdown.  I would definitely recommend watching any expected sessions know and see if this gets worse around 15:00, or if it remains the same, in which case the problem is elsewhere.  You must also eliminate everything else - the disks, network, etc.

  Good luck

  John Brady

• SIZE OF THE REDO LOG FILE

  
  Hello

  I got an error message when I add me new group. log files I searched and found the answer on the form. Ago 4 M minimum size of 11 g R2 log file size.

  My question is why a log file size depends on DB_BLOCK_SIZE? This parameter is set to the component structures of memory that create an instance when a log file is an operating system file that depend on the version of the OS not DB_BLOCK_SIZE.

  Thank you.

  
  SQL > alter database add logfile group 4 'c:\app\asif\oradata\employee\redo04.log' size 1 m;
  alter database add logfile group 4 'c:\app\asif\oradata\employee\redo04.log' size 1 m
  *
  ERROR on line 1:
  ORA-00336: 2048 blocks the size of the log file is minimum lower than 8192 blocks

  
  SQL > show parameter db_block_size

  VALUE OF TYPE NAME
  ------------------------------------ ----------- ------------------------------
  Whole DB_BLOCK_SIZE 8192
  SQL >

  You are assuming that the redo log block size is the same as the database block size. This is not correct.

  The error indicates that 8192 is the minimum number of blocks of a redo log file. The documentation states that the minimum size is 4 M. For example, you can deduct your redo log block size is 512 bytes.

  Here's some more information about the size of redo log, the documentation block.

  Unlike the database block size, which can always be between 2 K and 32 K, redo log default files to a block size that is equal to the size of physical sector of the disk. Historically, it is usually 512 bytes (512 b).

  Some new large disks offer 4K sizes byte (4K) to increase sector efficiency improved format and ECC capabilities. Most of the Oracle database platforms are able to detect this bigger sector size. The database then automatically creates files redo log with a block size of 4 K of these discs.

• How to change the location of the redo log files... ?

  I want all my redo log files to be created in \u10 instead of/U01 current?
  How to do? NOARCHIVELOG mode database on Oracle 10 g R2.
  Thank you
  Smirh

  user517525 wrote:
  Thank you
  Smirh

  [Move Redo Log members | http://download.oracle.com/docs/cd/B19306_01/server.102/b14231/onlineredo.htm#sthref951]

• At the time to rename the redo log file, I got the following error.

  SQL > host moves D:\oracle\product\10.2.0\oradata\test\redo02.log D:\oracle\produc
  t\10.2.0\oradata\test\re.log
  The process cannot access the file because it is being used by another process.

  This isn't a surprise if you do not rename the file also with SQL statements before the move in the OS layer. Did you?

  Add above: If you just want to get a group of newspapers moved to another directory, the right way to do that would be
  (1) to create the new group to the destination of your choice
  (2) the old Group drop
  (3) delete the old OS layer group

  This is done online, while the instance continues to run in the OPEN State.

  Kind regards
  Uwe Hesse

  http://uhesse.WordPress.com

  Published by: Uwe Hesse on 29.07.2010 12:08

• Question about how Oracle manages the Redo logs

  Hello
  
  Assuming a configuration which consists of 2 redo log groups (groups A and B), each group of 2 disks (disks A1 and A2 for Group A) and B1 and B2 disks for Group B. Additionally, assume that each redo log file resides by itself in a disk storage device and that the device is dedicated to her. So in the situation described above, there are 4 discs, one for each redo log file, and each disc contains nothing other than a redo log file. Also, assume that the database is in ARCHIVELOG mode and the files from archive is stored on another different set of devices.
  
  kind of graphically:
  

      GROUP A             GROUP B
  
        A1                  B1
        A2                  B2

  The question is: when the disks that make up the Group A are filled and Oracle switches to the disks in the Group B, can the group drives to take offline, perhaps even physically removed from the system if necessary without affecting the functioning of the database? Can the archiver process temporarily delayed until the disks (which have been removed) are presented online or is the DBA have to wait until the end of the process to archive a copy of the redo log file creating in archive?
  
  Thank you for your help,
  
  John.

  Hello
  A journal of the groups fall

  To remove a group of online redo logs, you must have the ALTER DATABASE system privilege. Before you delete a line redo log group, consider the following precautions and restrictions:

  * An instance requires at least two groups of files logging online, regardless of the number of members in the groups. (A group is one or more members.)
  * You can delete a group of newspapers online redo only if it is inactive. If you need to drop the current group, first force a log switch occurs.
  * Make sure a group of online redo logs is archived (if archiving is enabled) before dropping. To see if this happens, use the view LOG V$.

  SELECT GROUP #, ARCHIVED, STATUS FROM V$ LOG;

  GROUP # ARC STATUS
  --------- --- ----------------
  1 ACTIVE YES
  2. NO CURRENT
  3 INACTIVE YES
  4 INACTIVE YES

  Delete a group of newspapers online redo with the SQL ALTER DATABASE statement with the DROP LOGFILE clause.

  The following statement drops redo log group number 3:

  ALTER DATABASE, DROP LOGFILE GROUP 3;

  When a group of online redo logs is deleted from the database, and you do not use Oracle managed files, operating system files are not removed from the disk. Instead, control of the associated database files are updated to remove members of the Group of the database structure. After deleting a group of online redo logs, make sure the drop completed successfully and then use the command of operating system appropriate to delete the dropped online redo log files.

  When you work with files managed by Oracle, the cleaning of operating system files is done automatically for you.
  Your database will not be affected as you can work with 2 files, redo log in each group, as the minimum number of redo log in a database file is two because the process LGWR (newspaper writer) writes in the redo log in a circular way. If the process crashes because you have 2 groups only if you want to remove 1 Add a third and make that the current group and 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 find the configuration state of REDO logs files?

  I'm trying to move the redo log files.
  Before that, I want to know if it is set as a duplex or any other configuration.
  
  How to find the REDO log configurations.
  
  Oracle 10g R2
  
  Thank you
  Smith

  Example:

  Not in duplex redo log - if the number of members is 1, it is not duplex:

  SQL> select group#, members from v$log;
  
      GROUP#    MEMBERS
  ---------- ----------
           1          1
           2          1
           3          1
  
  SQL> select group#, member from v$logfile;
  
      GROUP# MEMBER
  ---------- --------------------------------------------------
           1 /u01/app/oracle/oradata/db1/redo01.log
           2 /u01/app/oracle/oradata/db1/redo02.log
           3 /u01/app/oracle/oradata/db1/redo03.log
  
  SQL> alter database add logfile member '/u01/app/oracle/oradata/db1/redo01_2.log' to group 1;
  
  Database altered.
  
  SQL> alter database add logfile member '/u01/app/oracle/oradata/db1/redo02_2.log' to group 2;
  
  Database altered.
  
  SQL> alter database add logfile member '/u01/app/oracle/oradata/db1/redo03_2.log' to group 3;
  
  Database altered.
  

  Duplex redolog

  SQL> select group#, members from v$log;
  
      GROUP#    MEMBERS
  ---------- ----------
           1          2
           2          2
           3          2
  
  SQL> select group#, member from v$logfile;
  
      GROUP# MEMBER
  ---------- --------------------------------------------------
           1 /u01/app/oracle/oradata/db1/redo01.log
           2 /u01/app/oracle/oradata/db1/redo02.log
           3 /u01/app/oracle/oradata/db1/redo03.log
           1 /u01/app/oracle/oradata/db1/redo01_2.log
           2 /u01/app/oracle/oradata/db1/redo02_2.log
           3 /u01/app/oracle/oradata/db1/redo03_2.log
  

• The clause in the database log file duplicate

  I tried to duplicate a database (Oracle RAC 10 g ASM 2 node Windows 2003 Server R2) and in the document of the oracle, it went something like:
  
  DUPLICATE the TARGET DATABASE to dupdb
  PFILE = /dup/oracle/dbs/initDUPDB.ora
  LOGFILE
  ' / dup/oracle/oradata/trgt/redo01.log' SIZE 200 K,.
  ' / dup/oracle/oradata/trgt/redo02.log' SIZE 200 K,.
  ' / dup/oracle/oradata/trgt/redo03.log' SIZE 200 K;
  
  I thought as the source database RMAN backup already contained the definitions of redo log. Are only these redo log files used for the process during replication of the database? Is the logfile clause is required to use the command DUPLICATE TARGET DATABASE?
  
  Thank you much in advance.

  LOG file can be used to specify where the newspapers of recovery for the duplicate database should be placed. This clause is not mandatory and it is really necessary only if you intend to rename the redo log files. If you don't need/want to rename the files, you can use the NOFILENAMECHECK option.

• That redo log files waiting?

  Hello Experts,

  I read articles on the log redo and undo segment files. I was wondering something very simple. That redo log files waiting in there? It stores the sql statements?

  Lets say that my update statement to modify 800 blocks of data. A unique single update statement can modify different data 800 right blocks? Yes, it may be true. I think that these data blocks can not hold buffers to the log to roll forward, right? I mean I know exactly what to do redo log buffer and redo log file. And I know that the task of backgrounding LGWR. But, I wonder if she she holds the data blocks? It is not supposed to hold data like cache buffer blocks, right?

  My second question is, rollback isn't effect to restore the newspaper to the right buffer? Because it does not need log buffer for effect do it again. Conversely, the restoration; statement is included in the restore log buffer by progression when someone isse, am I right?

  As far as I know, rollback interact directly with UNDO TABLESPACE?

  I hope that I have to express myself clearly.

  Thanks in advance.

  Here's my question:

  My second question is, rollback isn't effect to restore the newspaper to the right buffer? Because it does not need log buffer for effect do it again. Conversely, the restoration; statement is included in the restore log buffer by progression when someone isse, am I right?

  As far as I know, rollback interact directly with UNDO TABLESPACE?

  Yes, where else would the undo data come from? Undo tablespace contains the Undo segments that contain the Undo data required for the restoration of your transaction.

  I can say that rollback does not alter the data of the log buffer rede to the past. In other words, change vectors will be remain the same before restoration. Conversely, rollback command is also recorded in the log file of restoration by progression. As the name, all orders are saved in the REDO LOGS.

  I hope that I am wrong so far?

  Not sure why you even the buffer log roll forward for Rollback? This is the reason why I asked you it was for, where occurs the dose the cancellation? And the answer for this is that it happens in the buffer cache. Before you worry about the drivers of change, you must understand that it is not serious what contains where as long as there is no transaction recorded in the operating of the Undo segment table. If the operating table indicates that the transaction is longer there, there must be a cancellation of the transaction. Vectors of change are saved in the file log roll forward, while the restore happens on blocks of data stored in the file "data" undo blocks stored in the undo file "data".

  At the same time I read an article about redo and undo. In this article process transaction is explained. Here is the link http://pavandba.files.wordpress.com/2009/11/undo_redo1.pdf

  I found some interesting information in this article as follows.

  It is worth noting that during the restore process, recovery logs never participate. The only time where redo logs are read is retrieving and archiving. This is the concept of tuning key: redo logs are written on. Oracle does not read during normal processing. As long as you have sufficient devices so that when the ARC is reading a file, LGWR's writing to a different device, then there no contention for redo logs.

  If redo logs are never involved in the restoration process, how is it Oracle will then know the order of the transaction? As far as I know it is only written in redo logs.

  I have thoughts very amazed to Aman.

  Why you ask?

  Now, before giving a response, I say two things. One, I know Pavan and he is a regular contributor to this forum and on several other forums Facebook and two, with all due respect to him, a little advice for you, when you try to understand a concept, to stick to the Oracle documentation and do not read and merge articles/blog-posts from the web. Everone, which publishes on the web, has their own way to express things and many times, the context of the writing makes it more confusing things. Maybe we can erase the doubts that you can get after reading the various search results on the web.

  Redo logs used for the restoration, not to restore. The reason is the redo log files are applied in sequential order, and this is not the case when we look for the restoration. A restore is required to do for a few blocks away. Basically, what happens in a restoration, is that the records of cancellation required for a block of data are sought in the reverse order of their creation. The entry of the transaction is in the slot ITL of the block of data that point to the necessary undo bytes Address (UBA) using which oracle also knows what that undo the blocks would be necessary for the restoration of your transaction. As soon as the blocks of data will be cancelled, the ITL slots would be cleared as well.

  In addition, you must remember, until the transaction is not qualified as finished, using either a commit or a rollback, the cancellation of this data would remain intact. The reason for this is that oracle would ensure that undo data would be available to make the cancellation of the transaction. The reason why Undo data are also recorded in the journals of recovery is to ensure that in the event of the loss of the cancellation of the data file, retrieving them would be possible. Because it would also require changes that's happened on the blocks cancel, restore the vectors change associated with blocks of cancellation are also saved in the buffer log roll forward and, in the redo log files.

  HTH

  Aman...

• DB restore Archives not lost mode redo log file... restore from controlfile tr

  I have a 11g database I had taken an archive backup but has failed to take redo backup of log files...
  so, while I restored the PB... after formatting the machine... the oracle instance does not start.
  
  
  I create controlfile track but when I run it I get errors.
  given that I don't have the old log files... How can I get around this issue
  Thank you
  Here is the example of trace control file... Note that I can't create the redo log file
  given that the db will not climb up, it must be in mode nonmount
  and here's my created controlfile...
  CREATE CONTROLFILE REUSE DATABASE "XE" NORESETLOGS NOARCHIVELOG
  MAXLOGFILES 16
  MAXLOGMEMBERS 3
  MAXDATAFILES 100
  MAXINSTANCES 8
  MAXLOGHISTORY 292
  LOGFILE
  GROUP 1
  ' C:\ORACLEXE\APP\ORACLE\FLASH_RECOVERY_AREA\XE\ONLINELOG\O1_MF_1_80L7C259_. JOURNAL"
  SIZE 50 M 512 BLOCKSIZE,
  GROUP 2
  ' C:\ORACLEXE\APP\ORACLE\FLASH_RECOVERY_AREA\XE\ONLINELOG\O1_MF_2_80L7C375_. JOURNAL"
  SIZE 50 M BLOCKSIZE 512
  -STANDBY LOGFILE
  DATA FILE
  ' C:\ORACLEXE\APP\ORACLE\ORADATA\XE\SYSTEM. DBF',.
  ' C:\ORACLEXE\APP\ORACLE\ORADATA\XE\UNDOTBS1. DBF',.
  ' C:\ORACLEXE\APP\ORACLE\ORADATA\XE\SYSAUX. DBF',.
  ' C:\ORACLEXE\APP\ORACLE\ORADATA\XE\USERS. DBF'
  CHARACTER SET AL32UTF8
  ;
  
  I do not have these 2 files... what should I do to work around this situation
  ' C:\ORACLEXE\APP\ORACLE\FLASH_RECOVERY_AREA\XE\ONLINELOG\O1_MF_1_80L7C259_. JOURNAL"
  SIZE 50 M 512 BLOCKSIZE,
  GROUP 2
  ' C:\ORACLEXE\APP\ORACLE\FLASH_RECOVERY_AREA\XE\ONLINELOG\O1_MF_2_80L7C375_. JOURNAL"
  SIZE 50 M BLOCKSIZE 512
  -STANDBY LOGFILE
  DATA FILE
  
  Published by: zycoz100 on February 27, 2013 22:57

  If you have a backup to cold (closing correctly database) without the redo logs, change this:

  CREATE CONTROLFILE REUSE DATABASE "XE" NORESETLOGS NOARCHIVELOG
  

  TO

  CREATE CONTROLFILE REUSE DATABASE "XE" RESETLOGS NOARCHIVELOG
  

  You need to change the NORESETLOGS RESETLOGS for Oracle to recreate online redo logs.

  Hemant K Collette

• new with OMF online redo log files

  Hi all
  
  I'm using Oracle 11 g 2, I created my DB using Oracle managed (OMF) files.
  
  I wanted to re size my recovery connects so I went in an old redo logs fall and create a new.
  
  That was how my redo logs resembles. It was created by the creation of the DB with OMF format:

  .../app/oradata/ORCL11/onlinelog/o1_mf_1_6pfncw81_.log
  .../app/flash_recovery_area/ORCL11/onlinelog/o1_mf_1_6pfncx5z_.log
  .../app/oradata/ORCL11/onlinelog/o1_mf_2_6pfncxps_.log
  .../app/flash_recovery_area/ORCL11/onlinelog/o1_mf_2_6pfncz1v_.log
  .../app/oradata/ORCL11/onlinelog/o1_mf_3_6pfnczhd_.log
  .../app/flash_recovery_area/ORCL11/onlinelog/o1_mf_3_6pfnd0vw_.log

  using the script I created new below redo logs

  alter database add logfile group 1 (
  '.../app/oradata/ORCL11/onlinelog/redo1.log',  
  '.../app/flash_recovery_area/ORCL11/onlinelog/redo1.log') size 76m reuse;

  .........
  and I added the new redo log group
  

  alter database add logfile group 4 (
  '.../app/oradata/ORCL11/onlinelog/redo4.log',  
  '.../app/flash_recovery_area/ORCL11/onlinelog/redo4.log') size 76m reuse;

  I was not able to create the recovery logs, where is the name of the redo log file: o1_mf_1_6pfncw81_.log, since this is the format OMF.
  
  My question by creating my recovery connects the way does it have an impact? on the archiving of newspapers of recovery? any impact on the database for now, this isn't OMF?
  
  How can I create my redo logs with OMF format?
  
  Kind regards

  try: -.
  alter database add logfile Group 4;

  for example; -.

  SQL> alter database add logfile group 4;
  
  Database altered.
  
  SQL> select member from v$Logfile;
  
  MEMBER
  --------------------------------------------------------------------------------
  /home/u01/app/oracle/oradata/dbtest/redo03.log
  /home/u01/app/oracle/oradata/dbtest/redo02.log
  /home/u01/app/oracle/oradata/dbtest/redo01.log
  /home/u01/app/oracle/flash_recovery_area/DBTEST/onlinelog/o1_mf_4_75nmw33l_.log
  
  SQL> alter database add logfile group 5 size 100m;
  
  Database altered.
  
  SQL> select member from v$logfile;
  
  MEMBER
  --------------------------------------------------------------------------------
  /home/u01/app/oracle/oradata/dbtest/redo03.log
  /home/u01/app/oracle/oradata/dbtest/redo02.log
  /home/u01/app/oracle/oradata/dbtest/redo01.log
  /home/u01/app/oracle/flash_recovery_area/DBTEST/onlinelog/o1_mf_4_75nmw33l_.log
  /home/u01/app/oracle/flash_recovery_area/DBTEST/onlinelog/o1_mf_5_75nmyvjg_.log
  

  Published by: rajeysh on August 28, 2011 20:00

• What is the role of the archived in an incremental backup redo log files?

  I want to know, to which RMAN reads what block of data is changed after the last incremental backup.
  and what is the role of the archived in an incremental backup redo log files?
  
  Please guide.

  Hello

  First Querstion response->
  Each block of data in a data file contains a system change number (SCN), which is the SCN of the last change to the block. During an incremental backup, RMAN reads the RCS of each block of data in the input file and compares at the checkpoint SCN of the incremental backup from parent. If the RCS in the block of input data is greater than or equal to checkpoint SCN of the parent, then RMAN copies the block.

  2 - the archived redolog files are required for the restoration of the online of rman incremental backup in a consistent state.

  Thank you & best regards
  Rahul Sharma

• Redo log entries to the online redo log files

  Hello

  I'm a little confused about the redo log entries.

  I learned that LGWR writes redo log entries in the SGA, in redo log files in the following situation:

  -3 seconds after the last validation

  -redo log buffer has 1 MB

  -redo log buffer data 1/3

  When I take a transaction and if I change the wrong data, I have to cancel this transaction BUT the right now,

  What happens if the LGWR writes redo log disk entries?

  Is the bad transaction committed at all times?

  2791011 wrote:

  Hello

  I'm a little confused about the redo log entries.

  I learned that LGWR writes redo log entries in the SGA, in redo log files in the following situation:

  -3 seconds after the last validation

  -redo log buffer has 1 MB

  -redo log buffer data 1/3

  When I take a transaction and if I change erroneous data, I have to cancel this transaction at this time, BUT

  What happens if the LGWR writes redo log disk entries?

  Is the bad transaction committed at all times?

  DML changes are "permanent" after that VALIDATION is issued.

  When any COMMIT is issued, then changes can be undone.

• Bandwidth of the network for the redo log switches

  Hi all

  I'm using Oracle 11 g R2, I want to clarify the necessary bandwidth of my primary site to the secondary site (using Oracle Data guard)

  My database is an Oracle RAC 2 nodes each node has a log size to 2 GB again. listen to this file in operation every 5 minutes. It means that I'm spending a 2 GB redo log file every 5 minutes from each node. This means that 4 GB in total every 5 minutes.

  I'm planing to set up Oracle Dataguard in maximum performance mode. Is that mean I need a link between the primary and secondary site that is able to transfer files of 2 GB + 2 GB every 5 minutes?

  I do the calculation below and need your advice:

  4 GB / (5x60s) = 13981 KByte/s

  This means that I need to link to 13981x8bites/s = 111, 848Kbit/s?

  Is the above correct? your advice please

  Kind regards

  Please check below two

  http://www.Oracle.com/au/products/database/MAA-WP-10gR2-dataguardnetworkbestpr-134557.PDF

  How to calculate bandwidth transfer network required recovery in care of data (Doc ID 736755.1)

• importance of the size of the Redo Log

  Hi guys,.

  What is the importance of the size of the size of Redlog?

  whether large or small size?

  Thanks in advance

  REDA

  What is the importance of the size of the size of Redlog?

  Setting up a database of Performance

  Manage the Redo Log