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Oracle® Database Reference
10g Release 1 (10.1)

Part Number B10755-01
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Physical Database Limits

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 of 20,000 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 KB

Number of tablespaces cannot exceed the number of database files, as each tablespace must include at least one file

Bigfile Tablespaces Number of blocks 232 (4 GB) blocks
Smallfile (traditional) Tablespaces Number of blocks 222 (4 MB) blocks