1. 5 Copyright © 2005, Oracle. All rights reserved. Managing Database Storage Structures

2. 5-2 Copyright © 2005, Oracle. All rights reserved. Objectives After completing this lesson, you should be able to do the following: Describe how table row data is stored in blocks Define the purpose of tablespaces and data files Create and manage tablespaces Obtain tablespace information Describe the main concepts and functionality of Automatic Storage Management (ASM)

3. 5-3 Copyright © 2005, Oracle. All rights reserved. Storage Structures Database Tablespace Segment Extent Oracle data block LogicalPhysical OS block OS file

4. 5-4 Copyright © 2005, Oracle. All rights reserved. How Table Data Is Stored Tablespace Table ATable B Segment Rows Columns Table Blocks Row piece Extent

5. 5-5 Copyright © 2005, Oracle. All rights reserved. Anatomy of a Database Block Block header Free space Row data Growth

6. 5-6 Copyright © 2005, Oracle. All rights reserved. Tablespaces and Data Files The Oracle database stores data logically in tablespaces and physically in data files. Tablespaces: –Can belong to only one database –Consist of one or more data files –Are further divided into logical units of storage Data files: –Can belong to only one tablespace and one database –Are a repository for schema object data Database Tablespace Data files

7. 5-7 Copyright © 2005, Oracle. All rights reserved. Space Management in Tablespaces Locally managed tablespace: –Free extents are managed in the tablespace. –A bitmap is used to record free extents. –Each bit corresponds to a block or group of blocks. –The bit value indicates free or used extents. –The use of locally managed tablespaces is recommended. Dictionary-managed tablespace: –Free extents are managed by the data dictionary. –Appropriate tables are updated when extents are allocated or unallocated. –These tablespaces are supported only for backward compatibility.

8. 5-8 Copyright © 2005, Oracle. All rights reserved. Creating a New Tablespace

9. 5-9 Copyright © 2005, Oracle. All rights reserved. Creating a New Tablespace (Notes Only Slide)

10. 5-10 Copyright © 2005, Oracle. All rights reserved. Storage for Locally Managed Tablespaces

11. 5-11 Copyright © 2005, Oracle. All rights reserved. Storage for Locally Managed Tablespaces Full Notes Page

12. 5-12 Copyright © 2005, Oracle. All rights reserved. Tablespaces in the Preconfigured Database SYSTEM SYSAUX TEMP UNDOTBS1 USERS EXAMPLE

13. 5-13 Copyright © 2005, Oracle. All rights reserved. Tablespaces in the Preconfigured Database Full Notes Page

14. 5-14 Copyright © 2005, Oracle. All rights reserved. Altering a Tablespace

15. 5-15 Copyright © 2005, Oracle. All rights reserved. Altering a Tablespace Full Notes Page

16. 5-16 Copyright © 2005, Oracle. All rights reserved. Altering a Tablespace Full Notes Page

17. 5-17 Copyright © 2005, Oracle. All rights reserved. Actions with Tablespaces

18. 5-18 Copyright © 2005, Oracle. All rights reserved. Actions with Tablespaces Full Notes Page

19. 5-19 Copyright © 2005, Oracle. All rights reserved. Dropping Tablespaces

20. 5-20 Copyright © 2005, Oracle. All rights reserved. Viewing Tablespace Information

21. 5-21 Copyright © 2005, Oracle. All rights reserved. Where We Are Using tablespaces to separate data Creating various types of tablespaces Managing tablespaces Obtaining tablespace information Describe the main concepts and functionality of Automatic Storage Management (ASM)

22. 5-22 Copyright © 2005, Oracle. All rights reserved. What Is Automatic Storage Management? Is a portable and high-performance cluster file system Manages Oracle database files Spreads data across disks to balance load Mirrors data Solves many storage management challenges ASM File system Volume manager Application Database Operating system

23. 5-23 Copyright © 2005, Oracle. All rights reserved. ASM: Key Features and Benefits Stripes files, but not logical volumes Provides online disk reconfiguration and dynamic rebalancing Allows for adjustable rebalancing speed Provides redundancy on a per-file basis Supports only Oracle database files Is cluster aware Is automatically installed

24. 5-24 Copyright © 2005, Oracle. All rights reserved. ASM: Concepts Database Tablespace Segment Extent Oracle data block Data file Physical block ASM disk ASM file Allocation unit File system file or Raw device ASM disk group

25. 5-25 Copyright © 2005, Oracle. All rights reserved. Summary In this lesson, you should have learned how to: Describe how table row data is stored in blocks Define the purpose of tablespaces and data files Create and manage tablespaces Obtain tablespace information Describe the main concepts and functionality of ASM, such as: –Disk mirroring –Dynamic rebalancing –ASM disk groups

26. 5-26 Copyright © 2005, Oracle. All rights reserved. Practice Overview: Managing Database Storage Structures This practice covers the following topics: Creating tablespaces Gathering information about tablespaces