Create  a  database which implicitly creates a SYSTEM Rollback Segment in a SYSTEM tablespace. Create a Second Rollback Segment name R0  in the SYSTEM tablespace. Make  new  rollback segment available (After shutdown, modify init.ora file and Start database) Create other tablespaces (RBS)  for rollback segments. Deactivate  Rollback ...

samiksc

 Profile Answers by samiksc Questions by samiksc

• Dec 29th, 2005

Create rollback segment by using command likecreate rollback segment rbs01 tablespace tbs1 storage (initial 1M next 1M optimal 5M minextents 20 maxextents 100)Edit the database initialization file to ...

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 Rollback  segment  dynamically  extent  to handle larger transactions entry loads. A  single  transaction may wipeout all available free space in the Rollback Segment Tablespace. This prevents other user using Rollback segments.

Guest

• Dec 29th, 2005

A select query may fail with a 'snapshot too old' error in the following situation:A user issues a long running select query.Another user starts a transaction which updates the same table used in the ...

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 Querying the DBA_ROLLBACK_SEGS viewIN USE         - Rollback Segment is on-line.AVAILABLE - Rollback Segment available but not on-line.OFF-LINE  - Rollback Segment off-lineINVALID        - Rollback Segment Dropped.NEEDS RECOVERY  - Contains data but need recovery or corupted.PARTLY  AVAILABLE  - Contains...

samiksc

 Profile Answers by samiksc Questions by samiksc

• Dec 29th, 2005

The following views help in monitoring rollback segment usage: DBA_SEGMENTSDBA_ROLLBACK_SEGSV$ROLLNAMEV$ROLLSTATV$TRANSACTION

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 They allow the database to maintain read consistency between multiple transactions.

Anu

• Oct 4th, 2006

1.Transaction Rollback-When a transaction is rolled back to restore the old image.2.Transaction recovery-To undo any uncommitted changes when DB is open after instance failure.3.Read consistency-While transaction is on progress other users in DB do not see any uncommitted changes.

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 It  is  the  set  of  before  image  data blocks that contain rows that are modified by a transaction.Each   Rollback  Segment  entry  must  be  completed  within   one rollback segment. A single rollback segment can have multiple rollback segment entries.

samiksc

 Profile Answers by samiksc Questions by samiksc

• Dec 29th, 2005

A rollback segment entry consists of image of pre-update value, block address, data file number, transaction ID and transaction status (active or committed). A single rollback segment may contain several rollback entries and several active transactions.

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      - Logical Backups     - Cold Backups     - Hot Backups (Archive log)

cmanne

 Profile Answers by cmanne Questions by cmanne

• Jan 4th, 2006

1. Physical Backup---Hot Backup---Cold Backup2. Logical Backup---Export---Import

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 Full back      - Complete databaseIncremental          - Only affected tables from last incremental date/full backup date.Cumulative backup - Only affected table from the last cumulative date/full backup date.

cmanne

 Profile Answers by cmanne Questions by cmanne

• Jan 4th, 2006

Different kinds of Exports are:1. Owner(Schema) level Backup2. Object(table) level backup3. Full Backup4. Tablespace Level Backup

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 Taking backup of archive log files when database is open. For this the ARCHIVELOG mode should be enabled. The following files need to be backed up. All data files. All Archive log, redo log files. All control files.

cmanne

 Profile Answers by cmanne Questions by cmanne

• Jan 4th, 2006

The database should be in Archive log mode to take hot backups.Step1: Shutdown the database gracefullyStep2: Take full backup of the databaseStep3: Edit the following intialization parameters likelog_...

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Ravi Prakash Pichika

• Jun 6th, 2005

SGA - Stands for System Global Area, its a part of Memory structure! SGA consists of   Shared Pool Database Buffer Cache Redo Log Buffer Lock & Latch Management  & M...

nishit patel

• Mar 12th, 2005

SGA * stands for System/Shared Global Area* can be used/shared by all users* it is a part of memory structure of Instance* consists of memory components like 1> shared pool 2> Database cache 3...

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Answered by: Alok

• Sep 10th, 2005

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Redo log buffer is circular buffer,lgwr writes these buffers in cyclic faishon.redo log buffers contains redo entreies which are used to reconstruct or redo chandes. 
 

Alok

• Sep 10th, 2005

Redo log buffer is circular buffer,lgwr writes these buffers in cyclic faishon.redo log buffers contains redo entreies which are used to reconstruct or redo chandes.  

priya

• May 30th, 2005

It is a memory location where the temporary changes are stored in abuffer

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schma16

 Profile Answers by schma16 Questions by schma16

• May 29th, 2007

Optimal Flexible Architecture is a set of configuration standard created to ensure reliable Ora installation that require little maintenance. It has a default file naming and Directory layout for nami...

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Answered by: Lachi on 2005-06-08 07:28:04For perticular transaction Alter system set rollback segment 'name'; For database, we can set in pfile. Rollback_segment='name'

Lakshminarayan.

• Jun 13th, 2005

In above answer one correction is there,  For perticular transaction we can use fallowing syntax.  >set transaction use rollback segment 'name'

Lachi

• Jun 8th, 2005

For perticular transaction Alter system set rollback segment 'name'; For database, we can set in pfile. Rollback_segment='name'

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agarwalk_2000

 Profile Answers by agarwalk_2000 Questions by agarwalk_2000

• Jun 16th, 2007

By Dba_segments and DBA_extents and dba_free_space views.

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agarwalk_2000

 Profile Answers by agarwalk_2000 Questions by agarwalk_2000

• Jun 16th, 2007

Calculate the total header size.Calulate the available data space?per data block.Calulcate the combined column length by the avarge row.Calultate total average?row size.Calculate avarge number of rows that can fit in data block.Calulate the number of blocks?bytes that required for a table.

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simakas

 Profile Answers by simakas Questions by simakas

• Oct 9th, 2007

Yes. Using raw files/devices for database can have a slight performance gain. Raw files are unformatted disk partitions that can be used as one large file. Raw devices have the benefit of no file syst...

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bijan Mohapatra

• Nov 5th, 2006

Edit itit.ora file after shutdown the data base, set path for another control file in the parameter setting. then copy the control file to the desired location where the path is setting, then start the database.

Shrikant Pande

• Aug 25th, 2005

1. Edit init.ora file set control_files parameter with multiple location 2. shutdown immediate 3. copy control file to multiple locations & confirm from init.ora contol_files parameter ...

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anandhi80

 Profile Answers by anandhi80 Questions by anandhi80

• Jun 28th, 2006

when a user updated a particular table (for example 100 rows)...the old value will be retained in the roll back segments(Oracle 8) and now it is Undo segment (oracle 9i). If the user issue a rollback ...

Mahendra

• Sep 2nd, 2005

Used to store undo data. In a transaction when data is updated , other seesions should not view the uncommited data . Other Sessions will access the undo dara in the Roll Back segment

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simakas

 Profile Answers by simakas Questions by simakas

• Oct 9th, 2007

Segment is droppedOn shrinkOn truncation (TRUNCATE used with drop option)

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simakas

 Profile Answers by simakas Questions by simakas

• Oct 9th, 2007

Oracle raw devices are managed only with Oracle tools, at OS level they are just dd (character special files) devices. Raw devices are more difficult to administer than data files stored on a file system or in an ASM disk group.

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 Export the user Perform import  using  the  command  imp  system/manager   file=export.dmp indexfile=newrite.sql. This will create all definitions into newfile.sql. Drop necessary objects. Run the script newfile.sql after altering the tablespaces. Import from the backup for the necessary objects.

simakas

 Profile Answers by simakas Questions by simakas

• Oct 9th, 2007

If its the same database use:alter table the_table move tablespace other_tablespace; alter index the_index rebuild tablespace other_tablespace;

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