Flash Recovery Area

The Flash recovery area is a disk destination that is used by Oracle as a storage location for all recovery- and fault tolerance-related files.

RMAN will use it as a default location for backups. Remember that the flash recovery area is not only intended for RMAN’s exclusive use;

it is also, typically, used for multiplexed online logs, for a control file copy and as an archive log destination.

The advantage of directing RMAN backups to the flash recovery area is that Oracle can manage space in the recovery area very effectively: when it fills up,

Oracle will automatically delete any files within it that are obsolete, according to whatever rules for obsolescence you establish.

Oracle Scheduler Concepts

Oracle provides advances scheduler capabilities through the database Scheduler. To simplyfy management tasks, as well as offering a high rich set of functionality for complex scheduling needs, Oracle provides a collection of functions and procedures in the DBMS_SCHEDULER package. Collectively, these functions are called the Scheduler, and they are callable from any PL/SQL program.

What can the Scheduler Do ?

The Scheduler provide complex enterprise scheduling functionality, which you can use to:

1. Schedule job execution based on time.

2. Reuse existing programs and schedules

3. Schedule job processing in a way that models your business requirements

4. Manage and monitor jobs

5. Execute and manage jobs in a clustered environment

Thanks/

A.F.MD.IQBAL

Sr. Programmer

STANDARD GROUP

Database Security-1

Oracle Transparent Data Encryption (TDE)


#) Oracle Transparent Data Encryption addresses the encryption problem by deeply embedding encryption in the Oracle database.

#) Oracle database automatically encrypts the data before writing the information to disk. Subsequent select operations will have the data transparently decrypted so the application will continue to work normally.

#) Encryption works by passing clear text data along with a secret, known as the key, into an encryption program. The encryption program encrypts the clear text data using the supplied key and returns the data encrypted.

#) Oracle Wallet, uses certificates from a Certificate Authority, by which Administrator initialize DB master key.


#) TDE uses the External Security Module (ESM) to generate encryption keys, to provide functions for encryption and decryption, and to store encryption keys securely inside and outside the database.

->** When a table contains encrypted columns, a single column key is used regardless of the number of encrypted columns in that table. The keys for all tables containing encrypted columns are stored in a single column in a dictionary table in the database. That column is encrypted with the database server’s master key, preventing any use of those keys through unauthorized access. The master key is stored in a wallet outside the database. The wallet is created using Oracle Wallet Manager, and the master key is generated by the ESM.

Preparation for OCP 10g Exam

Now I am preparing for OCP 10g Exam after got my OCA. But I think that this won't be as easy as the OCA. It needs lots of read and practice. From now on I will try my self to write something about OCP exam related topics which help me to understand and catch the Oracle Administration.

Here is now its main titles which need to address for the exam.



1. Configuring Recovering Manager (RMAN)



2. Using Recovery Manager .



3. Recovering from Non-critical losses.



4. Database Recovery



5. Flashback



6. Dealing with Database Corruption



7. Monitoring and Managing Memory.



8. Automatic Performance Management.



9. Managing Schema Objects.



10. Managing Storage.



11. Automatic Storage Management.



12. Managing Resouces.



13. Austomatic Tasks with Scheduler.



14. Database Security.



15. Using Globalization Support.

OCA 10g

At last after long read and practice and time I got my OCA 10g certification. I am now Happy. Though I read from 2002 to get a certification, but I think it is better to have 10g than 8i. Because 10g is far better than 8i and has lots of feature and very much auto tuned and also easy to install.

I am reading to got OCP now, hope to pass it. Also have wish to learn Linux.....

Steps to create a Database Manually

1. Decide a unique SID
2. Set the OS variables (in unix / linux)
3. Create the parameter file

Important Parameters are :

a. DB_NAME

b. DB_DOMAIN

c. CONTROL_FILES

d. DB_BLOCK_SIZE

e. UNDO_MANAGEMENT

f. UNDO_TABLESPACE

4. Create and Set Oracle Service
5. Create password file
6. Start the Instance in NOMOUNT mode.
7. Create the DB : issue the Create Database Command:



CREATE DATABASE [database name]

[CONTROLFILE REUSE]

[LOGFILE [GROUP integer] file specification]

[MAXLOGFILES integer]

[MAXLOGMEMBERS integer]

[MAXLOGHISTORY integer]

[MAXDATAFILES integer]

[MAXINSTANCES integer]

[ARCHIVELOGNOARCHIVELOG]

[CHARACTER SET charset]

[NATIONAL CHARACTER SET charset]

[DATAFILE filespec [autoextend]]

[DEFAULT TEMPORARY TABLESPACE tablespace filespec]

[UNDO TABLESPACE tablespace DATAFILE filespec]
[SET TIME_ZONE [time_zone_region]];

A working example of a CREATE DATABASE script follows:


create database ora10
logfile group 1 ('D:\oracle\databases\ora10\redo1.log') size 10M,
group 2 ('D:\oracle\databases\ora10\redo2.log') size 10M,
group 3 ('D:\oracle\databases\ora10\redo3.log') size 10M
character set WE8ISO8859P1
national character set utf8
datafile 'D:\oracle\databases\ora10\system.dbf'
size 50M
autoextend on
next 10M maxsize unlimited
extent management local
sysaux datafile 'D:\oracle\databases\ora10\sysaux.dbf'
size 10M
autoextend on
next 10M
maxsize unlimited
undo tablespace undo
datafile 'D:\oracle\databases\ora10\undo.dbf'
size 10M
default temporary tablespace temp
tempfile 'D:\oracle\databases\ora10\temp.dbf'
size 10M;

8. Execute the Scripts that generate the Data Dictionary Views.

- CATALOG.sql for data dictionary views
- CATPROC.sql for objects required to use PL/SQL.
- SQL> @?/rdbms/admin/catalog.sql
- SQL> @?/rdbms/admin/catproc.sql

9. Create Server Parameter File from Pfile.
10. Backup the DB (cold backup)
11. Create Additional Tablespaces

Guidelines for OFA

1. Create a different directory under the Oracle Home Directory for each Database.
2. Place the Control files, Redo Log files and Datafiles under the database specific
directory.
3. Separate Groups of objects with different fragmentation characteristics.
4. Separate Objects that will contend for disk resources.
5. Separate Groups of objects with different behavioral characteristics.
6. Store at least two copies of Control files on different physical drives.
7. Store the two online Redo Log Members of a Group on different drives.

How ADDM Computes Thresholds

Metric baselines are named snapshots of a target's past performance.

When baseline metrics are gathered, the AWR stores the high value and the low value for each metric. The technique that ADDM uses to compute a baseline threshold depends on the comparison operator that is used for spcifying the threshold , and on the associated high and low value.

If the metric comparison operator is a greater than (>), the warning threshold for the metric is computed as

Metric High Value * (1+Warning Percentage/100)

If the metric comparison is a less than (<), the warning threshold for the metric is computed as

Metric Low Value * (1-Warning %/100)

For example, if the high value for the metric Current Open Cursors Count is 500,

* the 85 percent warning threshold is 500*(1+85/100)= 925
* the 95 percent critical threshold is 500*(1+95/100)=975

raising an warning alert whenever the Current Open Cursos Count exceeds 925 or raising a critical alert whenever the Current Open Cursors Count exceeds 975.

if the low value for the metric Large Pool Free % is 300 MB,

* the 85 percent warning threshold is 300*(1-85/100) = 45 MB
* the 95 percent critical threshold is 300*(1-95/100) = 15 MB

raising a warning alert whenever the percentage of free space in the Large Pool fals below 45 MB or raising a critical alert whenever the free space in the Large Pool falls below 15 percent.

OCP 10g

I am working with Oracle since 2001 in Standard Group. Mainly I am a PL/SQL Programmer and Forms/Reports developer. I also know basic of Database Administration. Now I want to learn Database Administration very well. So that I decided to give OCP 10g 1zo-042 Exam, as early as possible.

Though it is not easy but it is very important for my career . I need to know the theory and also practice it to know the reality.

From now on, I will use this blog to save the my articles and tips regarding OCP Exam. I also want to share my knowledge with others.

Database is very curcial for any organization. A DBA is not only responsible for to protect the data of database but also responsible to keep the databse available 7x24 and at very good performance. Poor functions also degrade orgainization works speed. So its also a very challanging job .