Oracle FAQs Questions with Answers # 1

What is Log Switch? 

The point at which ORACLE ends writing to one online redo log file and begins writing to another is called a log switch. 

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 process LGWR. The on-line redo log files are used in cyclical fashion. 

Which parameter specified in the DEFAULT STORAGE clause of CREATE TABLESPACE cannot be altered after creating the tablespace? 

All the default storage parameters defined for the tablespace can be changed using the ALTER TABLESPACE command. When objects are created 
their INITIAL and MINEXTENS values cannot be changed. 

What are the steps involved in Database Startup? 

Start an instance, Mount the Database and Open the Database. 

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 at the time of the failure. Resolving any pending distributed transactions undergoing a two-phase commit at the time of the instance failure. 

Can Full Backup be performed when the database is open? 


What are the different modes of mounting a Database with the Parallel Server? 

Exclusive Mode If the first instance that mounts a database does so in exclusive mode, only that Instance can mount the database.  Parallel Mode If the first instance that mounts a database is started in parallel mode, other instances that are started in parallel mode can also mount the database. 

What are the advantages of operating a database in ARCHIVELOG mode over operating it in NO ARCHIVELOG mode ? Complete database recovery from disk failure is possible only in ARCHIVELOG mode. Online database backup is possible only in ARCHIVELOG mode. 

What are the steps involved in Database Shutdown? 

Close the Database, Dismount the Database and Shutdown the Instance. 

What is Archived Redo Log? 

Archived Redo Log consists of Redo Log files that have archived before being reused. 

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. 

What is Partial Backup? 

A Partial Backup is any operating system backup short of a full backup, taken while the database is open or shut down. 

What is Mirrored on-line Redo Log? 

A mirrored on-line redo log consists of copies of on-line redo log files physically located on separate disks, changes made to one member of the group are made to all members. 

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. 

Can a View based on another View? 


Can a Tablespace hold objects from different Schemes? 


Also read:

Have a Oracle Question
Do you have an Oracle Question?

Oracle Books
Oracle Certification, Database Administration, SQL, Application, Programming Reference Books

Oracle Application
Oracle Application Hints and Tips

Oracle Home
Oracle Database, SQL, Application, Programming Tips

All the site contents are Copyright © and the content authors. All rights reserved.
All product names are trademarks of their respective companies.
The site is not affiliated with or endorsed by any company listed at this site.
Every effort is made to ensure the content integrity.  Information used on this site is at your own risk.
 The content on this site may not be reproduced or redistributed without the express written permission of or the content authors.