The Oracle database is the first database that is designed for the enterprise grid computing. It is the most flexible and cost–effective way to manage information and application.
Oracle’s grid computing technology includes:
- Automatic Storage Management (ASM)
- Real Application Cluster (RAC)
- Oracle streams
- Enterprise Manager Grid Control
Oracle Database 11g:- ‘g’ stands for grid.
- Automatic Storage Management spreads database data across all disks, creates and maintains a storage grid and provides the highest I/O throughput in with minimal management cost. ASM redistributes the all data automatically. There is no need for a logical volume manager to manage the file system.
- Oracle’s Real Application Cluster runs and scales all application workloads on a cluster of servers and offers the following features :
- Oracle Streams provides a unified framework for information sharing, combining, message queuing, data replication, event notification, data warehouse loading and publishing into a single technology.
- Enterprise Manage Grid Control manages grid wide operations that include managing the entire stack of software, provisioning users, cloning databases, and managing patches.
USER PROCESS:
A database user who needs to request information from the database must first make connection with the Oracle Server.
SESSION:
A session represents the state of the current user login to the database instance.
INSTANCE:
An Oracle instance contains the set of Oracle Database background processes that operate on the stored data and the shared allocated memory that those processes use to do their work.
SERVER PROCESS:
Oracle Database creates server processes to handle the requests of user processes connected to an instance.
Server processes are two type 🡪
- Dedicated Server Process, which can services only one user process.
- Shared Server Process, which can services multiple user process.
CONNECTION AND SESSION LAYOUT
One Session for each Connection
One Connection for two Session
ORACLE SHARED SERVER:- The SHARED_SERVERS initialization parameter specifies the minimum number of shared servers that you want created when the instance is started.
DATABASE SHARED SERVER PROCESS
ORACLE DEDICATED SERVER:- A dedicated server process, which services only one user process.
DATABASE SEDICATED SERVER PROCESS
The following example connects SQL*Plus to the database as user SYSTEM and enables tracing, thus creating a new session.
- DATABASE SERVER ARCHITECTURE OVERVIEW
An Oracle Database consists of a database and at least one instance.
An instance, or database instance, is the combination of memory and processes that are a part of a running installation and a database is a set of files that store data.
DATABASE SERVER ARCHITECTURE
IDENTIFY THE CORRECT SESSSION AND TERMINATE THE SESSION BY PERFORMING THE STEPS BELOW:-
- Invoke sql*plus.
- HOW TO CHECK THE SESSION
SELECT SID, SERIAL#, STATUS, SERVER
FROM V$SESSION
WHERE USERNAME = ‘<username>’
- HOW TO KILL THE SESSION
ALTER SYSTEM KILL SESSION ‘<SID, SERIAL#>’
IDENTIFY THE CORRECT SESSSION AND TERMINATE THE SESSION BY PERFORMING THE STEPS BELOW:-
NOTES:- Oracle Enterprise Manager 9.2 was used in the examples.
- Select START > Programs > Oracle > OraHome92 > Enterprise Manager Console. Select Launch Standalone and click OK.
- Expand Databases. Expand your database. Expand Instance and select Sessions. Identify the session you want to terminate.
- Expand Sessions. Select the session you want to terminate and click Kill Session.
