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Oracle 数据库的限制(9iR2)

2004-07-20 16:18 417 查看

Physical Database Limits

[thead] [/thead]
ItemType of LimitLimit Value
Database Block SizeMinimum
2048
bytes; must be a multiple of operating system physical block size
MaximumOperating system dependent; never more than 
32
KB
Database BlocksMinimum in initial extent of a segment.
2
blocks
Maximum per datafilePlatform dependent; typically 
2
22
-1
blocks
ControlfilesNumber of control files
1
minimum; 
2
or more (on separate devices) strongly recommended
Size of a control fileDependent on operating system and database creation options; maximum of 
20,000
x (database block size)
Database filesMaximum per tablespaceOperating system dependent; usually 
1022
Maximum per database
65533
May be less on some operating systems Limited also by size of database blocks and by the 
DB_FILES
initialization parameter for a particular instance
Database extentsMaximum
4
GB, regardless of the maximum file size allowed by the operating system
Database file sizeMaximumOperating system dependent. Limited by maximum operating system file size; typically 
2
22 or 
4
M blocks
MAXEXTENTS
Default valueDerived from tablespace default storage or 
DB_BLOCK_SIZE
initialization parameter
MaximumUnlimited
Redo Log FilesMaximum number of logfilesLimited by value of 
MAXLOGFILES
parameter in the 
CREATE DATABASE
statement Control file can be resized to allow more entries; ultimately an operating system limit
Maximum number of logfiles per groupUnlimited
Redo Log File SizeMinimum size
50
KB
Maximum sizeOperating system limit; typically 
2
GB
TablespacesMaximum number per database
64
K Number of tablespaces cannot exceed the number of database files, as each tablespace must include at least one file

Process and Runtime Limits

[thead] [/thead]
ItemTypeLimit
Instances per database
Maximum number of cluster database instances per databaseOperating system-dependent
LocksRow-levelUnlimited
Distributed Lock ManagerOperating system dependent
SGA sizeMaximum valueOperating system-dependent; typically 
2
to 
4
GB for 32-bit operating systems, and > 
4
GB for 64-bit operating systems
Advanced Queuing ProcessesMaximum per instance
10
Job Queue ProcessesMaximum per instance
1000
I/O Slave ProcessesMaximum per background process (DBWR, LGWR, etc.)
15
Maximum per Backup session
15
SessionsMaximum per instance
32
KB; limited by the 
PROCESSES
and 
SESSIONS
initialization parameters
Global Cache Service ProcessesMaximum per instance
10
Shared ServersMaximum per instanceUnlimited within constraints set by the 
PROCESSES
and 
SESSIONS
initialization parameters, for instance
DispatchersMaximum per instanceUnlimited within constraints set by 
PROCESSES
and 
SESSIONS
initialization parameters, for instance
Parallel Execution SlavesMaximum per instanceUnlimited within constraints set by 
PROCESSES
and 
SESSIONS
initialization parameters, for instance
Backup SessionsMaximum per instanceUnlimited within constraints set by 
PROCESSES
and 
SESSIONS
initialization parameters, for instance
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