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

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)

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

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

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

5-7 Copyright © 2005, Oracle. All rights reserved. Oracle Managed Files (OMF) Specify file operations in terms of database objects rather than file names. ParameterDescription DB_CREATE_FILE_DEST Defines the location of the default file system directory for data files and temporary files DB_CREATE_ONLINE_LOG_DEST_n Defines the location for redo log files and control file creation DB_RECOVERY_FILE_DEST Defines the location for RMAN backups Example: SQL> ALTER SYSTEM SET DB_CREATE_FILE_DEST = '/u01/oradata'; SQL> CREATE TABLESPACE tbs_1;

5-8 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.

5-9 Copyright © 2005, Oracle. All rights reserved. Exploring the Storage Structure Click the links to view detailed information.

5-10 Copyright © 2005, Oracle. All rights reserved. Creating a New Tablespace

5-11 Copyright © 2005, Oracle. All rights reserved. Creating a New Tablespace (Notes Only Slide)

5-12 Copyright © 2005, Oracle. All rights reserved. Storage for Locally Managed Tablespaces

5-13 Copyright © 2005, Oracle. All rights reserved. Storage for Locally Managed Tablespaces Full Notes Page

5-14 Copyright © 2005, Oracle. All rights reserved. Tablespaces in the Preconfigured Database SYSTEM SYSAUX TEMP UNDOTBS1 USERS EXAMPLE

5-15 Copyright © 2005, Oracle. All rights reserved. Tablespaces in the Preconfigured Database Full Notes Page

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

5-17 Copyright © 2005, Oracle. All rights reserved. Altering a Tablespace Full Notes Page

5-18 Copyright © 2005, Oracle. All rights reserved. Altering a Tablespace Full Notes Page

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

5-20 Copyright © 2005, Oracle. All rights reserved. Actions with Tablespaces Full Notes Page

5-21 Copyright © 2005, Oracle. All rights reserved. Dropping Tablespaces

5-22 Copyright © 2005, Oracle. All rights reserved. Viewing Tablespace Information

5-23 Copyright © 2005, Oracle. All rights reserved. Gathering Storage Information

5-24 Copyright © 2005, Oracle. All rights reserved. Viewing Tablespace Contents 12061_1_sel_ts_3

5-25 Copyright © 2005, Oracle. All rights reserved. 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

5-26 Copyright © 2005, Oracle. All rights reserved. What Is Automatic Storage Management? 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

5-27 Copyright © 2005, Oracle. All rights reserved. ASM: Key Features and Benefits ASM 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

5-28 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

5-29 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 Automatic Storage Management (ASM)

5-30 Copyright © 2005, Oracle. All rights reserved. Practice Overview: Managing Database Storage Structures This practice covers the following topics: Creating tablespaces Gathering information about tablespaces