Category Archives: Oracle Database

An Oracle database is a collection of data treated as a unit. The purpose of a database is to store and retrieve related information. A database server is the key to solving the problems of information management.Many companies has implemented their data in Oracle. Most of them are mission critical. So Oracle database concept need to be very clear to manage these mission critical things. At the same time Oracle database needs to deliver high performance also. A database server also prevents unauthorized access and provides efficient solutions for failure recovery.

Below section I have tried to present all the important features in Oracle Database management

How to find the waitevent History of the Oracle session

In this post , we will look at the different queries to retrieve the waitevent history of the Oracle session. History of wait events in a specific session from start can be found using below query set lines 120 trimspool on col event head “Waited for” format a30 col total_waits head “Total|Waits” format 999,999 col tw_ms head “Waited|for (ms)” format 999,999.99 col aw_ms head “Average|Wait … Continue reading How to find the waitevent History of the Oracle session »

What you need to know about Oracle Flashback query

Oracle has introduced Flashback Technology  that let you view past states of database objects or to return database objects to a previous state without using point-in-time media recovery. With flashback features, you can do the following: Perform queries that return past data Perform queries that return metadata that shows a detailed history of changes to the database Recover tables or rows to a previous point … Continue reading What you need to know about Oracle Flashback query »

Must Read Oracle Database Cloud Service Overview and various options

Introduction to Oracle Database Cloud Service Oracle database cloud service is an service of Cloud Category PaaS. It enables businesses to reap all the benefits of Platform as a Service, including subscription-based, self-service access to reliable, scalable, and elastic cloud environments. Earliar you need to purchase hardware ,install OS and then install Oracle software and create database for using the database. Now You can be … Continue reading Must Read Oracle Database Cloud Service Overview and various options »

How To Check Environment Variables for a Running Process

This post we will talking about one of the useful things which administrator often has to use. The topic is How To Check Environment Variables for a Running Process . Let’s first start with what is environment variable and then find out How To Check Environment Variables for a Running Process in different flavor of Unix systtem What is environment Variable An environment variable is a dynamic-named … Continue reading How To Check Environment Variables for a Running Process »

How to use Virtual Index in Oracle

Last updated on September 21st, 2017 at 05:23 pmWhat is  Virtual Index in Oracle ? a) A virtual index is a “fake” index whose definition exists in the data dictionary, but has no associated index segment. b) Many time tuning advisor recommends you creating new index and you want to test the new index. In this case It can take good amount of time to … Continue reading How to use Virtual Index in Oracle »

All Useful 11g Dynamic Performance Views

What is Oracle Dynamic Performance Views Oracle Dynamic Performance Views is a set of views(V_$) which are defined over very low level Oracle views called the X$ views View. We have views for complete set of operations. V$ names are synonyms which point to the V_$ views What is X$view :The X$ views are very low level representations of Oracle internal database structures. They are … Continue reading All Useful 11g Dynamic Performance Views »

Top 46 Oracle ASM Interview Questions

Oracle ASM is widely used in IT industry. Here I have compiled Top 46 Oracle ASM Interview Questions to enhance the knowledge about Oracle ASM instance Question 1 What is ASM in Oracle? Answer Oracle ASM is Oracle’s volume manager specially designed for Oracle database data. It is available since Oracle database version 10g and many improvements have been made in versions 11g release 1 and … Continue reading Top 46 Oracle ASM Interview Questions »

Pre-Built Oracle database for learning and testing using Oracle Developer VM

Oracle developer day pre-installed virtual machine is very useful to perform lab testing on Oracle database. It is very helpful for practicing about Oracle database on Linux machine on your laptop. You can also export your application database and import into this pre-installed oracle VM, It is very quick and easy to setup. Here is the steps to setup Oracle developer day VM  Please note that … Continue reading Pre-Built Oracle database for learning and testing using Oracle Developer VM »

Virtual IP Addresses : VIP in Oracle RAC

Last updated on September 17th, 2017 at 05:42 pmWhat is VIP in Oracle RAC? High Availability (HA) databases are less than satisfactory if database clients are unable to connect or reconnect quickly when planned or unplanned downtime causes one or more instances to become unavailable. Database clients use TNS descriptors to contact a TNS listener on one of the cluster nodes from a list of … Continue reading Virtual IP Addresses : VIP in Oracle RAC »

What is voting disks in RAC

Last updated on April 1st, 2017 at 08:09 amVoting Disks in RAC Description Voting disk is a file that manages information about node membership.It is located on the shared cluster system or a shared raw device file or ASM(11gr2 onwards) .Its primary purpose is to help in a situation where the private network communication fails.CSS (Cluster Synchronization Service) is the service that determines which nodes … Continue reading What is voting disks in RAC »

Demonstration/Viewlet/Videos for Many Oracle features

Oracle has provided lot  of Demonstration/Viewlet/Videos on Oracle features like RMAN,Flashback,standby etc Each demonstration has a description and links to the demo.  Some demos have a ‘demo’ link that will play in your browser on any platform.  Others have a ‘download’ link which will download an executable file to your computer that will only play on a Windows system. Some demos offer both options. Here … Continue reading Demonstration/Viewlet/Videos for Many Oracle features »

How to resolve ORA-00904: invalid identifier

ORA-00904: invalid identifier is one of the common error seen. Reference: Oracle documentation One of the most common cause of this error Invalid identifier means the column name entered is either missing or invalid. It also Some time comes  when you used reserved word in Oracle database. Check List to resolve the ORA error  It comes when you put extra comma in the create table … Continue reading How to resolve ORA-00904: invalid identifier »