Oracle Apps DBA Training - DBA Technologies

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WELCOME TO DBA TECHNOLOGIES
ORACLE DATABASE ARCHITECTURE
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By Mr.
PRASAD MYNUMPATI
18 Years Real Time in
INDIA-USA
http//www.dbatechnologies.net/
www.dbatechnologies.net Building Career With
Passion
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• Architecture
• Main components of Architecture
• 1. ORACLE INSTANCE
• SGA (Memory)
• Background Process
• 2. ORACLE DATABASE
• Storage Level

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• 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

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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

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Instance Architecture
SGA - Mandate and Optional memory structures and
background processes
Streams Pool
Large
DBWn
LGWR
SMON
PMON
CKPT
RECO
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• 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

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• 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 support from failures
• Supports up to 8 file copies

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• 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

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• 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

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• 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

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DB Architecture Control files
minimum 1. Stores Database structural
information. Recommended 3 files.
Disk1 Control
Disk2 Control
Disk3 Control
Data files Minimum 3 from 10g. Stores data
permanently for retrieval purpose.
System
Undo
Sysaux
Redo log files Minimum -2 holds all changes in
the form of changes vectors for recovery
Rego1a .log
Redo2a .log
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Oracle Server Oracle Server is the
combination of Oracle Instance Oracle database.
Database access is only via Instance
SGA
Database
gt
Select
DBBC
SP
From Emp User Process
Control Redo Data Files
LC
DDC
REDO LOG BUFFERS Back ground Processes
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Logical and Physical aspect of Oracle
database
DATABASE
PHYSICAL
LOGICAL
Control Files
Tables
Views
Data Files
Procedures
Redo Log Files
Triggers
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IS INSTANCE PHYSICAL OR LOGICAL ? PHYSICAL
LOGICAL
INSTANCE
?
NEITHER
IT IS VOLATILE
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ORACLE Database TS Architecture
SYSTEM TABLE SPACE
SYSAUX TABLESPACE
UNDO TABLESPACE
TEMPORARY TABLESAPCE
DATA TABLESPACE
INDEX TABLESPACE
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Database Architecture SYSTEM TS

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

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

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Database
Architecture UNDO TS

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

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Building career with passion
QUESTION AND ANSWER SESSION
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