Oracle Dba Online Training -dba Technologies 554kv

WELCOME TO DBA TECHNOLOGIES ORACLE DATABASE ARCHITECTURE – 1 By Mr. PRASAD MYNUMPATI 18 Years Real Time in INDIA-USA

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Architecture

Main components of Architecture 1. ORACLE INSTANCE

SGA (Memory) & Background Process 2. ORACLE DATABASE

Storage Level

ORACLE Instance Architecture – SGA

What is ORACLE INSTANCE? Physical Memory (SGA) & Processes SGA should be able to open in physical memory

What is SWAP? Swap also a type of file system on HDD, it is used by OS when Real memory usage is at high

Swap must be available before installing Oracle Software

Oracle Instance Architecture – PROCESSES

Each connection to UNIX operating system is process While starting up instance – SGA (Memory Structures) – Background Process ($ps) Background process are required to manage memory structures and database files. Some of the important background process are: DBWn, LGWR, SMON, PMON, ARCH,RECO

Instance Architecture SGA - Mandate and Optional memory structures and background processes

Streams Pool

Large DBWn

LGWR

SMON

PMON

CKPT

RECO

What is ORACLE DATABASE?

ORACLE DATABASE is a combination of 3 different types of files Different types of files (C,R,D) -Control Files -Redo log files -Data files

DB Architecture - Control Files

Control Files – Holds data about database structure (physical database structural information)

Importance of control file – Database can not be started with out control file – Multiplexing to from failures – s up to 8 file copies

DB Architecture – Control Files

Contents of Control file • Database Name and database id • Database creation date and time

• All database file names (data files) • Location of each data file • Age of each file (Checkpoint Information) • Current online log sequence number • Checkpoint number • Backup information

DB Architecture - Data File Data Files Stores actual data permanently in ORACLE proprietary files called data files. Data files are going to be on file system like -UNIX -EXT2 -EXT3 -NTFS (in case of windows)

Minimum 3 data base files are required from 10g -System -Undo -Sysaux

DB Architecture - Redo log files

Stores all changes in the form of change vectors for recovery Changes are saved to Data Files and Redo Log Files – what is the difference?

Changes to REDO LOG FILES are in the form of change vectors – Block id – File id

– Change details

Changes to Data files are in the form of rows and blocks

DB Architecture Control files : minimum 1. Stores Database structural information. Recommended 3 files. Disk1 Contro l

Disk2 Contro l

Disk3 Contro l

Data files : Minimum 3 from 10g. Stores data permanently for retrieval purpose.

System

Redo log files: Minimum -2 holds all changes in the form of changes vectors for recovery

Undo

Rego1a .log

Sysaux

Redo2a .log

Oracle Server Oracle Server is the combination of Oracle Instance & Oracle database. Database access is only via Instance

Database

SGA

> Select From Emp; Process

DBBC

SP LC

DDC

REDO LOG BUFFERS

Back ground Processes

Control Redo Data Files

Logical and Physical aspect of Oracle database DATABASE

PHYSICAL

LOGICAL

Control Files Data Files Redo Log Files

Tables Views Procedures Triggers

IS INSTANCE PHYSICAL OR LOGICAL ? LOGICAL

INSTANCE

PHYSICAL

?

NEITHER

IT IS VOLATILE

ORACLE Database TS Architecture SYSTEM TABLE SPACE

SYSAUX TABLESPACE

UNDO TABLESPACE

TEMPORARY TABLESAPCE

DATA TABLESPACE

INDEX TABLESPACE

Database Architecture – SYSTEM TS

s should not keep application data on SYSTEM tablespace.It is only to base tables like. TAB$ COL$ IND$ Base Tables are created during the creation of data base to metadata.

Database Architecture – SYSAUX TS SYSAUX tablespace introduced in version 10g s work load repository Reports such as AWR and ADDM willmake use of SYSAUX to generate reports Helps in understanding the performance at SERVER level

Database Architecture – UNDO TS

UNDO tablespace is to image during DML operations s Read consistency Flashback operations Rollback transactions Contents of UNDO TS type is UNDO it is not permanent

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QUESTION AND ANSWER SESSION

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