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分类: Oracle
2012-12-19 16:39:36
Item | Type of Limit | Limit Value |
---|---|---|
Database Block Size | Minimum | 2048 bytes; must be a multiple of operating system physical block size |
Maximum | Operating system dependent; never more than 32 KB | |
Database Blocks | Minimum in initial extent of a segment. | 2 blocks |
Maximum per datafile | Platform dependent; typically 222 - 1 blocks | |
Controlfiles | Number of control files | 1 minimum; 2 or more (on separate devices) strongly recommended |
Size of a control file | Dependent on operating system and database creation options; maximum of20,000 x (database block size) | |
Database files | Maximum per tablespace | Operating 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 extents | Maximum per dictionary managed tablespace | 4 GB * physical block size (with K/M modifier); 4 GB (without K/M modifier) |
Maximum per locally managed (uniform) tablespace | 2 GB * physical block size (with K/M modifier); 2 GB (without K/M modifier) | |
Database file size | Maximum | Operating system dependent. Limited by maximum operating system file size; typically 222 or 4 MB blocks |
MAXEXTENTS | Default value | Derived from tablespace default storage or DB_BLOCK_SIZE initialization parameter |
Maximum | Unlimited | |
Redo Log Files | Maximum number of logfiles | Limited 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 group | Unlimited | |
Redo Log File Size | Minimum size | 50 KB |
Maximum size | Operating system limit; typically 2 GB | |
Tablespaces | Maximum number per database | 64 K Number of tablespaces cannot exceed the number of database files because each tablespace must include at least one file |
Bigfile Tablespaces | Number of blocks | A 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 32K blocks and 32TB for a tablespace with 8K blocks. |
Smallfile (traditional) Tablespaces | Number of blocks | A 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 file | Maximum size | Dependent on the operating system. An external table can be composed of multiple files. |