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What is mean live dead lock? How to prevent it.?
prahlad_786
- Jun 23rd, 2010
Whenever you have competing DML running against the same data, you run the risk of a deadlock.Tune the application - Single-threading related updates and other application changes can often remove dea...
naveen5555
- Sep 22nd, 2007
A deadlock occurs when two or more users are waiting for data locked by each other(Not commited by user01).To fix this, recreate the segment with higher INITTRANS and/or PCTFREE values. This will allo...
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Backup Mode Redo Generation
Why more redos are generated when the database is in begin backup mode?
ddj1966
- May 28th, 2010
When a user managed Hot backup is executed, the tablespace or database has to be placed in backup mode. This informs the Oracle kernel that SCNs should not be updated on the datafile. i.e. the header ...
dhandapanik
- Dec 30th, 2009
During begin backup mode, the data file headers get freezed and it doesn’t get updated until the end backup. So it causes a checkpoint to the datafile. This causes all dirty blocks to be w...
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What do you mean by MEDIA RECOVERY..?
narendra05
- Apr 23rd, 2010
Recovery is method of making the database consitent. The database keeps this by way of SCN in headrer of all the datafile and controlfile. In case the SCN on datafile and controlfile database th...
kannan7
- Apr 15th, 2010
Media recovery is used to recover from a damaged(or lost) datafile, controlfile, or spfile. The goal of media recovery is to restore database integrity.
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How can I Export 9i data in 8 ? I mean when I Export from 9i and Import in 8, I face errors. what sould I do and my pc is not in Network.
narendra05
- Apr 23rd, 2010
I would suggest create a db link in Oracle 8 to Oracle 9i and run the CREATE TABLE AS SELECT FROM another database.I would suggest you move to Oracle 10g /11g soon as Oracle support is already stopped to 9i and 8i release.Narendra
sanjayoracle
- Apr 25th, 2008
We can do it. but first we have to confirm that parameter NLS_LANG is same in both database. otherwise in IMP process oracle will give error
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How do you verify and validate the Datafile which is backed up?
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What is Restricted Mode of Instance Startup ?
An instance can be started in (or later altered to be in) restricted mode so that when the database is open connections are limited only to those whose user accounts have been granted the RESTRICTED SESSION system privilege.
satish_manukonda
- Jan 24th, 2010
Restricted mode comes into picture when your taking backup and maintance activites. In the restricted mode no user is allowed to access..Bring the database to mount , that it will makes Restricted mode active.
satyam_2007
- Oct 25th, 2007
RESTRICT is one of an important option used with an open database.It performs a database startup with the database in the restricted user mode. User must having the privileges of RESTRICT, u...
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144. What is On-line Redo Log?
The On-line Redo Log is a set of tow or more on-line redo files that record all committed changes made to the database. Whenever a transaction is committed, the corresponding redo entries temporarily stores in redo log buffers of the SGA are written to an on-line redo log file by the background ...
oracleofdelphi
- Sep 9th, 2009
Online redologs name is used since archivelogs are called offline redologs. Online redologs can be in three states current to which lWr is currently writing transaction changes then this current beco...
samala
- Sep 15th, 2007
Redo logs records all the changes to the database? whether commited or uncommited. How does it know whether you are committing or rolling back till you commit it. Oracle always thinks positively that...
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What are the steps involved in Instance Recovery ?
Rolling forward to recover data that has not been recorded in data files, yet has been recorded in the on-line redo log, including the contents of rollback segments. Rolling back transactions that have been explicitly rolled back or have not been committed as indicated by the rollback segments regenerated in step a. Releasing any resources (locks) held by transactions in process...
oracleofdelphi
- Sep 9th, 2009
Crash recovery is performed by SMON when database started after an instance crash or after a shutdown abort. Since during crash current transactions are present in redolog files and not yet been wri...
krishna
- May 23rd, 2007
Steps involve in recovery1.Restore backup datafiles2.Recover using Archive log files 3.apply partial backup 4.recover using redo log files
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Can Full Backup be performed when the database is open ?
No.
Kamran Agayev A.
- Sep 8th, 2009
Of course YESUsing RMAN you can take full backup of database while it's open. But don't forget to archive current redo log file and backup it also, because it keeps all changes made to database while ...
sanjayoracle
- Apr 25th, 2008
NO, we can't. cuz Full Backup means consistent backup and we can take this backup only when our database is close.
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What is Full Backup ?
A full backup is an operating system backup of all data files, on-line redo log files and control file that constitute ORACLE database and the parameter.
oracleofdelphi
- Sep 9th, 2009
When using logical backup if we give full=y - that is a full backup.When using RMAN by default it takes full backup and image copy is also full backup since it contains all blocks used and not used on...
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How much time will it take a hotbackup if the batabase size is 60Gb
Mohammed Abdul Afroze
- Sep 28th, 2007
It depends on the datafiles related to database at OS Level.
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You have taken a manual backup of a datafile using o/s. How RMAN will know about it?
naveen_rc
- Aug 6th, 2009
Whenever we take any backup through RMAN, in the repository information of the backup is recorded. The RMAN respository can be either controlfile or recovery catalog. However if I take a backup throug...
subhash.terdale
- Oct 1st, 2008
Full backup is offline backup of datafiles, Parameter file, Controlfiles, Redologfiles
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Table Export
How we you identify if a table was exported in its life time?
rajesh_rd
- Mar 23rd, 2009
Refer cumulative or an incremental backup (export )we have a parameter (RECORD) & the default parameter is yes & is to track the incremental backup of a table so those backup (export...
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How to recover control file without backup and without 'create control file' command?
chetan.ind
- Mar 18th, 2009
If this is the situation, simple process is :1.?Take a trace of control file from clone do the changes in that like database name and datafile name and location.2. Save it as < name >.ora3. Run the f...
sanjayoracle
- Apr 25th, 2008
If we don;t have any backup of Controlfile...then we have to use create controlfile command..
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What are the different tools available for hot backups. Is it preferable to take it manually all the time or it depends on the size of the database.
bhendega
- Feb 24th, 2009
In oracle there are different tools for hot backup RMAN OEMAs per my view, it's de...
Chiranjeevi Manne
- Mar 30th, 2007
1. Using OS level filesystem backup tools 2. RMAN utility 3. Using traditional hot backup methos like keeping the tablespace in backup mode and the using OS level copy command to copy the datafiles to the backup location
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How to take cold and hot backup using UNIX
Sajeev123
- Jan 8th, 2009
Cold backup we can perform using OS commands after shutting down the database.In DB running position we can take hot backup using the following commans;alter database begin backup;
JOY
- Jun 12th, 2007
We can perform cold backup in unix by shutting down the database in proper mode so the control file will in consistent state and after that u can perform backing up all database files.I hot back we ca...
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Oracle log switch question
My database is in archive mode. when log switch occur that log file is archiving . what happens when log switch occurs
rupiy2k
- Dec 20th, 2008
After logswitch checkpoint accour.It update the hedder of datafile and controlfile with new SCN no. and checkpoint position.it also give the signal to dbwr to writ dirty buffer to datafile.
naveen5555
- Sep 22nd, 2007
Log switch event will take place. But the status of the log file which is archiving will be ACTIVE till it finish archiving.
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What is the difference between ntbackup and third party backup
Vinovidhupriya
- Dec 12th, 2008
One difference between NT Backup and full-blown, third-party backup utilities is the lack of an internal backup job scheduler. While most backup utilities can be set to run automatically at a certain ...
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RMAN Backup
Detail script of backup using RMAN in both mode catalog and nocatalog
MUNNU2U
- Nov 26th, 2008
Full Backup in the sense taking up the whole database backup into a specific folder or a path but we cant take any jobs as?backup and SQL Server logins?also we cant take.
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What are the steps involved in Database Startup ?
subhash.terdale
- Oct 1st, 2008
Steps involved in database startup are as follows Startup nomount - Instance starts, SGA allocated, Background processes started Used during database creation Startup mount - Control file read, d...
satyam_2007
- Oct 21st, 2007
There are the three steps need to follow to start database:1) Start an Instance.2) Mount the database.3) Open the database.Connect with operating system authentication:conncet / as sysdba1) Start an I...
Oracle Backup and Recovery Interview Questions
Ans