Sunday, 16 December 2012

Physical Database Limits in oracle 11g

Physical Database Limits

ItemType of LimitLimit Value
Database Block SizeMinimum2048 bytes; must be a multiple of operating system physical block size
Database Block SizeMaximumOperating system dependent; never more than 32 KB
Database BlocksMinimum in initial extent of a segment2 blocks
Database BlocksMaximum per datafilePlatform dependent; typically 222 - 1 blocks
ControlfilesNumber of control files1 minimum; 2 or more (on separate devices) strongly recommended
ControlfilesSize of a control fileDependent on operating system and database creation options; maximum of20,000 x (database block size)
Database filesMaximum per tablespaceOperating system dependent; usually 1022
Database filesMaximum per database65533
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 per dictionary managed tablespace4 GB * physical block size (with K/M modifier); 4 GB (without K/M modifier)
Database extentsMaximum per locally managed (uniform) tablespace2 GB * physical block size (with K/M modifier); 2 GB (without K/M modifier)
Database file sizeMaximumOperating system dependent. Limited by maximum operating system file size; typically 222 or 4 MB blocks
MAXEXTENTSDefault valueDerived from tablespace default storage or DB_BLOCK_SIZE initialization parameter
Redo Log FilesMaximum number of logfilesLimited by value of MAXLOGFILES parameter in the CREATE DATABASEstatement
Control file can be resized to allow more entries; ultimately an operating system limit
Redo Log FilesMaximum number of logfiles per groupUnlimited
Redo Log File SizeMinimum size4 MB
Redo Log File SizeMaximum SizeOperating system limit; typically 2 GB
TablespacesMaximum number per database64 K
Number of tablespaces cannot exceed the number of database files because each tablespace must include at least one file
Bigfile TablespacesNumber of blocksA bigfile tablespace contains only one datafile or tempfile, which can contain up to approximately 4 billion ( 232 ) blocks. The maximum size of the single datafile or tempfile is 128 terabytes (TB) for a tablespace with 32 K blocks and 32 TB for a tablespace with 8 K blocks.
Smallfile (traditional) TablespacesNumber of blocksA smallfile tablespace is a traditional Oracle tablespace, which can contain 1022 datafiles or tempfiles, each of which can contain up to approximately 4 million (222) blocks.
External Tables fileMaximum sizeDependent on the operating system.
An external table can be composed of multiple files.

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