1. 1 Copyright © 2005, Oracle. All rights reserved. Introduction

2. Copyright © 2005, Oracle. All rights reserved. 1-2 Objectives After completing this course, you should be able to do the following: –Install, create, and administer Oracle Database 10g Enterprise Edition –Configure the database for an application –Implement a backup and recovery strategy –Employ basic monitoring procedures After completing this lesson, you should be able to do the following: –Describe course objectives –Explain the Oracle Database 10g architecture

3. Copyright © 2005, Oracle. All rights reserved. 1-3 Oracle Products Oracle databases Oracle Application Server Oracle Applications Oracle Collaboration Suite Oracle Developer Suite Oracle services

4. Copyright © 2005, Oracle. All rights reserved. 1-4 Oracle Database 10g: “g” Stands for Grid Low cost High quality of service Easy to manage Storage grid Database grid Application grid Grid control Automatic Storage Management Real Application Clusters Oracle Streams Enterprise Manager Grid Control

5. Copyright © 2005, Oracle. All rights reserved. 1-5 Grid Full Notes Page

6. Copyright © 2005, Oracle. All rights reserved. 1-6 Oracle Database Architecture An Oracle server: Is a database management system that provides an open, comprehensive, integrated approach to information management Consists of an Oracle instance and an Oracle database

7. Copyright © 2005, Oracle. All rights reserved. 1-7 Database Structures Storage structures Memory structures Process structures Instance System Global Area (SGA) Background processes Database files DB structures - Memory - Process - Storage

8. Copyright © 2005, Oracle. All rights reserved. 1-8 Oracle Memory Structures Java pool Database buffer cache Redo log buffer Shared pool Large pool SGA Streams pool Server process 1 PGA Server process 2 PGA Background process PGA DB structures - Memory << - Process - Storage

9. Copyright © 2005, Oracle. All rights reserved. 1-9 Oracle Memory Structures Full Notes Page

10. Copyright © 2005, Oracle. All rights reserved. 1-10 Process Structures User process: Started at the time a database user requests a connection to the Oracle server Server process: Connects to the Oracle instance and is started when a user establishes a session Background processes: Started when an Oracle instance is started Instance SGA Background processes Server process PGA User process DB structures - Memory - Process << - Storage

11. Copyright © 2005, Oracle. All rights reserved. 1-11 Oracle Processes System Monitor (SMON) Database Writer (DBWn) Check- point (CKPT) LogWriter (LGWR) Process Monitor (PMON) Archiver (ARCn) Server process Server process Server process Server process System Global Area (SGA) Background processes

12. Copyright © 2005, Oracle. All rights reserved. 1-12 Server Process and Database Buffer Cache Buffers: Pinned Clean Free or unused Dirty DBWn Server process SGA Database buffer cache Data files

13. Copyright © 2005, Oracle. All rights reserved. 1-13 Physical Database Structure Online redo log files Password file Parameter file Archive log files Control files Data files Alert and trace log files Backup files DB structures - Memory - Process - Storage <<

14. Copyright © 2005, Oracle. All rights reserved. 1-14 Physical Database Structure Full Notes Page

15. Copyright © 2005, Oracle. All rights reserved. 1-15 Tablespaces and Data Files Tablespaces consist of one or more data files. Data files belong to only one tablespace. USERS tablespace Data file 1 Data file 2

16. Copyright © 2005, Oracle. All rights reserved. 1-16 SYSTEM and SYSAUX Tablespaces The SYSTEM and SYSAUX tablespaces are mandatory tablespaces. They are created at the time of database creation. They must be online. SYSTEM : For core functionality (for example, data dictionary tables) SYSAUX : Is auxiliary, for additional database components (such as the Enterprise Manager Repository)

17. Copyright © 2005, Oracle. All rights reserved. 1-17 Segments, Extents, and Blocks Segments exist within a tablespace. Segments are made up of a collection of extents. Extents are a collection of data blocks. Data blocks are mapped to disk blocks. SegmentExtentsData blocks Disk blocks

18. Copyright © 2005, Oracle. All rights reserved. 1-18 Logical and Physical Database Structures Database LogicalPhysical Tablespace Data file OS block Segment Extent Oracle data block Schema

19. Copyright © 2005, Oracle. All rights reserved. 1-19 Database Structures Full Notes Page

20. Copyright © 2005, Oracle. All rights reserved. 1-20 Enlarging the Database You can enlarge the database in the following ways: Creating a new tablespace Adding a data file to an existing tablespace Increasing the size of a data file Providing for the dynamic growth of a data file SYSTEM tablespace INVENTORY tablespace Database

21. Copyright © 2005, Oracle. All rights reserved. 1-21 Exploring the Storage Structure Click the links to view detailed information.

22. Copyright © 2005, Oracle. All rights reserved. 1-22 The HR Sample Schema JOB_HISTORY EMPLOYEE_ID (PK,FK) START_DATE (PK) END_DATE JOB_ID (FK) DEPARTMENT_ID (FK) EMPLOYEES EMPLOYEE_ID (PK) FIRST_NAME LAST_NAME EMAIL PHONE_NUMBER HIRE_DATE JOB_ID (FK) SALARY COMMISION_PCT MANAGER_ID (FK) DEPARTMENT_ID (FK) DEPARTMENTS DEPARTMENT_ID (PK) DEPARTMENT_NAME MANAGER_ID LOCATION_ID (FK) JOBS JOB_ID (PK) JOB_TITLE MIN_SALARY MAX_SALARY REGIONS REGION_ID (PK) REGION_NAME COUNTRIES COUNTRY_ID (PK) COUNTRY_NAME REGION_ID (FK) LOCATIONS LOCATION_ID (PK) STREET_ADDRESS POSTAL_CODE CITY STATE_PROVINCE COUNTRY_ID (FK)

23. Copyright © 2005, Oracle. All rights reserved. 1-23 Database Architecture: Summary of Structural Components Memory structures: –System Global Area (SGA): Database buffer cache, redo buffer, and various pools –Program Global Area (PGA) Process structures: –User process and Server process –Background processes: SMON, PMON, DBWn, CKPT, LGWR, ARCn, and others Storage structures: –Logical: Database, schema, tablespace, segment, extent, and Oracle block –Physical: Files for data, parameters, redo, and OS block

24. Copyright © 2005, Oracle. All rights reserved. 1-24 Database Architecture and Activities The following topics are covered in the remaining part of this lesson: Control files Oracle instance management Data files and Database Writer (DBWn) Checkpoints (CKPT) Redo log files and LogWriter (LGWR) Archiver (ARCn) System Monitor (SMON) Process Monitor (PMON) Example: How the Oracle database works

25. Copyright © 2005, Oracle. All rights reserved. 1-25 Control Files Contain physical database structure information Are read at mount stage Should be multiplexed to protect against loss Are required to access the database spfileorcl.ora CONNECT / AS SYSDBA STARTUP Instance Example Database files SGA

26. Copyright © 2005, Oracle. All rights reserved. 1-26 Oracle Instance Management System Monitor (SMON) Database Writer (DBWn) LogWriter (LGWR) Process Monitor (PMON) Archiver (ARCn) SGA Java pool Shared poolLarge poolStreams pool Database buffer cache Redo log buffer Checkpoint (CKPT)

27. Copyright © 2005, Oracle. All rights reserved. 1-27 Data Files Contain all database data Can be associated with only one database Form the logical unit of database storage called “tablespace” Are read into memory (in blocks) on request Should be secured by following a backup strategy SGA Database buffer cache Data files Database Writer (DBWn)

28. Copyright © 2005, Oracle. All rights reserved. 1-28 Database Writer (DBWn) DBWn writes when one of the following events occurs: Checkpoint Dirty buffers’ threshold No free buffers Timeout RAC ping request Tablespace OFFLINE Tablespace READ ONLY Table DROP or TRUNCATE Tablespace BEGIN BACKUP SGA Database buffer cache Data files Database Writer (DBWn) Background Information

29. Copyright © 2005, Oracle. All rights reserved. 1-29 Checkpoint (CKPT) Responsible for: Signaling DBWn at checkpoints Updating data file headers with checkpoint information Updating control files with checkpoint information Database Writer (DBWn) Checkpoint (CKPT) SGA Database buffer cache

30. Copyright © 2005, Oracle. All rights reserved. 1-30 Redo Log Files and LogWriter Redo log files: Record changes to the database Should be multiplexed to protect against loss LogWriter writes: At commit When one-third full Every three seconds Before DBWn writes Group 3 Log Writer (LGWR) Group 1Group 2 Redo log buffer SGA

31. Copyright © 2005, Oracle. All rights reserved. 1-31 Archiver (ARCn) Is an optional background process Automatically archives online redo log files when ARCHIVELOG mode is set for the database Preserves the record of all changes made to the database LogWriter (LGWR) Archiver (ARCn) Redo log buffer SGA

32. Copyright © 2005, Oracle. All rights reserved. 1-32 System Monitor (SMON) Performs instance recovery at startup Coalesces free space Deallocates temporary segments System Monitor (SMON) Instance SGA Other processes

33. Copyright © 2005, Oracle. All rights reserved. 1-33 Process Monitor (PMON) PMON cleans up the database buffer cache and frees resources after failed processes by: Rolling back the transaction Releasing locks Releasing other resources Instance SGA Other processes Server process PGA User process Process Monitor (PMON)

34. Copyright © 2005, Oracle. All rights reserved. 1-34 Oracle Instance Management: Summary System Monitor (SMON) Database Writer (DBWn) LogWriter (LGWR) Process Monitor (PMON) Archiver (ARCn) SGA Java pool Shared poolLarge poolStreams pool Database buffer cache Redo log buffer Checkpoint (CKPT)

35. Copyright © 2005, Oracle. All rights reserved. 1-35 How the Oracle Database Works Instance SGA Database Writer (DBWn) LogWriter (LGWR) Database buffer cache Redo log buffer Server process User process 1 2 3 Starting a database instance Establishing a connection

36. Copyright © 2005, Oracle. All rights reserved. 1-36 How the Oracle Database Works Instance SGA Database Writer (DBWn) LogWriter (LGWR) Database buffer cache Redo log buffer Server process User process 4 The user updates a row. 10 7 6 5 8 9 Processing a SQL statement

37. Copyright © 2005, Oracle. All rights reserved. 1-37 Summary In this lesson, you should have learned how to: Describe the course objectives Explain the Oracle Database 10g architecture

38. Copyright © 2005, Oracle. All rights reserved. 1-38 Database Architecture: Quiz Mark each of the following statements about an Oracle database as True or False: 1.Control files store information about the physical database structure. 2.Transaction changes are stored in redo log files. 3.Tablespaces consist of one or more data files. 4.A data file can be used for more than one tablespace. 5.LogWriter (LGWR) writes redo log entries to the disk. 6.Database Writer (DBWn) writes modified blocks from the buffer cache to the disk. 7.All Oracle background processes are optional.