balu

• Oct 8th, 2005

LGWR process wirtes all change vectors from theredo log buffer to online redo log file sequentially.

Answer Question  Select Best Answer

balu

• Oct 8th, 2005

When ever changes happend to the database previous change will be there in the rollback segment.

Answer Question  Select Best Answer

Kishore Kumar Vuthpala

• Apr 11th, 2006

Hit Ratio is the ratio of shared SQL and PL/SQL items found in the Library Cache versus physical storage.It can also be defined in a mathematical expression as  1 - ((physical reads) / (db block gets + consistent reads))

Answer Question  Select Best Answer

 Each block contains entries as followsFixed block headerVariable block headerRow Header,row date (multiple rows may exists)PCTEREE (% of  free space for row updation in future)

Anu

• Oct 3rd, 2006

A block is divided into1. Header2.free space3.data spaceThe free space is in the middle shrinks as header and data space grow.Space usage in the data space :The data space is managed with 2 parameters...

Answer Question  Select Best Answer

 To manage the database level transactions such as modifications of the data dictionary table that record information about the free space usage.

Anu

• Oct 3rd, 2006

1.System tablespace is required in all databases.2.It is created with the database.3.Contains the data dictionary and stored program units.4.Contains SYSTEM undo segment.

Answer Question  Select Best Answer

 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 ...

Answer Question  Select Best Answer

 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 ...

Answer Question  Select Best Answer

 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

Answer Question  Select Best Answer

 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.

Answer Question  Select Best Answer

 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.

Answer Question  Select Best Answer

      - 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

Answer Question  Select Best Answer

 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

Answer Question  Select Best Answer

 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_...

Answer Question  Select Best Answer

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...

Answer Question  Select Best Answer

Read Best Answer

Editorial / Best Answer

Answered by: 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. 
 

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

Improve Answer

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...

Answer Question  Select Best Answer

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'

Answer Question  Select Best Answer

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.

Answer Question  Select Best Answer

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.

Answer Question  Select Best Answer

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...

Answer Question  Select Best Answer