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Oracle RDBMS Server Articles

Performing a quick and efficient Performance Tuning audit

Checks to be performed at the machine level (note the example is Red Hat Linux)

run queue should be ideally not more than the number of CPU’s on the machine

At the maximum it should never be more than twice the number of CPU’s.

This is denoted by the column ‘r’ in the vmstat output shown below

vmstat – 5

face:/opt/oracle>vmstat 5
procs memory swap io system cpu
r b swpd free buff cache si so bi bo in cs us sy id wa
4 1 488700 245704 178276 12513572 0 1 10 17 48 1365 40 12 43 5

How to import table with custom type

When importing table that contained custom type, you will encounter an oracle error as shown below:
Import of table containing object type(s) fails with IMP-00061 IMP-00063

When you import a table that references a type, but a type of that name
already exists in the database. Import attempts to verify that the pre-existing
type is in fact the type used by the table(rather than a different type that
just happens to have the same name).

RMAN checksyntax

RMAN is recommended for backups/restore of oracle databases.It is a very powerful tool and has variety of useful features.There is 'checksyntax' feature in RMAN which allows one to check RMAN scripts syntactically without executing it.This feature is available from 10G release 2.It proves to be useful for checking scriptsfor live databases where one doesnt have leisure to execute scripts any time and any times!!

bash-3.00$ vi rman_bkp.rman

ALLOCATE CHANNEL c1 TYPE DISK FORMAT '/data/backup/Hotbkp_Full_%D_%d_%s_%p'; BACKUP database; RELEASE CHANNEL c1;
allocate channel c2 type dis

ORA_ROWSCN for capturing row level changes

I've been working on way to capture changed rows using ora_rowscn for part of an ETL routine. Here are some details of what I've tested and found.

By default, the ora_rowscn pseudo column reports the scn at block level. This means that rows sharing the same block will have the same ora_rowscn, and if one row were to be changed, then scn would be altered for both blocks.

Oracle 10g Data Guard – Quick Switchover with Physical Standby Database

Once the standby database is setup using Data Guard and works properly, you may want to test switchover, or perform switchover to reduce primary database downtime during OS upgrades or hardware upgrades. (To set up a Physical Standby database, please refer to my OraFAQ blog “Oracle 10g – Manually Create a Physical Standby Database Using Data Guard”.)

A switchover allows the primary database to switch roles with its standby database. There is no data loss during a switchover.

How to Identify OS or Oracle 64 bit or 32 bit

How to Identify OS or Oracle 64 bit or 32 bit on Unix
It is very common question which version of oracle I need to install. 32 bit or 64 bit? As a 64-bit operating system can support either a 32-bit database or a 64-bit database. A 32-bit operating system cannot support a 64-bit database. So, version identification of the OS is necessary prior to install oracle.

Oracle 10g - Manually Create a Physical Standby Database Using Data Guard

Step-by-step instructions on how to create a Physical Standby Database on Windows and UNIX servers, and maintenance tips on the databases in a Data Guard Environment.

Oracle 10g Data Guard is a great tool to ensure high availability, data protection and disaster recovery for enterprise data. I have been working on Data Guard/Standby databases using both Grid control and SQL command line for a couple of years, and my latest experience with Data Guard was manually creating a Physical Standby Database for a Laboratory Information Management System (LIMS) half a year ago.

Why I Choose Oracle as My Career?

Mohammad taj's picture

There are some question which asked frequently on forums from every oracle newbie.

1. Which Oracle Certification I choose ?

Here I will explain in details.

There types of Oracle Certification we can do.
1. Oracle DBA
2. Oracle Developer
3. Oracle Application DBA

1. Oracle DBA

The person which maintain Oracle Database called Oracle Database Administrator.
There are some frequent work for Oracle DBA
1. Database Backup Responsibity.
2. Database Performance Tunning
3. Database Basic Administration Like " user creation, database security"

How to compile Invalid Object?

Mohammad taj's picture

There are five ways to recompile invalid objects in schema.

5. Manually Recompile



This procedure is equivalent to the following SQL statement:


Exec dbms_ddl.alter_compile ( type , schema, name);
Schema : Database Username

Name : Objects name


Migrating Databases From NON-ASM to ASM

Mohammad taj's picture

Dear Friends,

In this article we focus on How to migrate existing database to ASM.

Login to SYSDBA user and alter below three parameter for controlfile,datafile or FRA location with SPFILE option.

1. First need to set below parameter for controlfile,datafile or FRA.

NOTE: I have two disk group here I am using "DGRP2" disk group.
SQL> alter system set control_files='+DGRP2' scope=spfile;
System altered.
SQL> alter system set db_create_file_dest='+DGRP2' scope=spfile;
System altered.