tablespaces（Datafile management in tablespaces）
• Tune I/O problems • Execute user-manager backups • Implement Oracle Managed Files • Obtain tablespaces and backup information • Introduce SQL Server/DB2 storage management
Tablespace (One or more datafiles)
Table Table Index
Index Index
Table
Index Index
Index Index
Table
Datafiles (Physical structures associated with only one tablespace)
• Non-SYSTEM tablespaces:
– Flexibility in database administration. – Separate data by backup requirements. – Separate dynamic and static data to enable database tuning. – Control space allocation for both applications and system
from more than one disk drive are assigned to a tablespace.
• Datafiles are always assigned to only one
database.
7-4
Tablespaces/Datafiles/Database Objects
• A tablespace belongs to only one database, and
has at least one datafile that is used to store data for the associated tablespace.
• A tablespace can span disk drives when datafiles
• Describe the logical structure of the database • Create tablespaces • Describe space management in tablespaces • Change the status of tablespaces • Change the size and storage settings of
7-3
Logical Structure of the Database
Tablespaces vs. Datafiles
Oracle uses tablespaces to logically organize data that are physically stored in datafiles.
disk drives to reduce I/O contention
• Separate rollback segment data from user data • Take individual tablespaces offline while others
remain online
• Reserve a tablespace for a particular type of
7-2
Overview
Data files
Control files
Redo log files
Physical Structure of the Database
Datafile1 Datafile2 Datafile3 Datafile4 Datafile5
SYSTEM
USER
Other
Tablespace Tablespace Tablespace
Objects(stored in tablespace may spawn several datafiles)
7-5
Advantages for Using Multiple Tablespaces
• Separate user data from data dictionary data • Separate one application's data from another's • Store different tablespaces' datafiles on separate
Managing Tablespaces and Data files User-Manager Backups
管理表空间和数据文件 用户管理的数据库备份
Objectives
After completing this lesson, you should be able to do the following:
database use, such as high update activity, readonly activity, or temporary segment storage.
• Back up individual tablespaces.
7-6
Logical Structure of the Database
users – Reduce contention for input/output path access (to/from
memory/disk)
7-8Βιβλιοθήκη Creating Tablespaces Command
7-7
Tablespace Types
• SYSTEM tablespace:
– Created with the database – Contains the data dictionary – Contains the SYSTEM undo segment – Should not contain user data, although it is allowed