Oracle 11g中数据库能有多大?

根据11g release 2文档《Oracle® Database Reference 11g Release 2 (11.2)》,我们可以计算出11g中数据库大小的一个理论极限:

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
Database Block Size Maximum Operating system dependent; never more than 32 KB
Database Blocks Minimum in initial extent of a segment 2 blocks
Database 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
Controlfiles 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
Database files 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)
Database extents 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
MAXEXTENTS Maximum Unlimited
Redo Log Files Maximum number of logfiles Limited by value of MAXLOGFILES parameter in the CREATE DATABASE statementControl file can be resized to allow more entries; ultimately an operating system limit
Redo Log Files Maximum number of logfiles per group Unlimited
Redo Log File Size Minimum size 4 MB
Redo Log File Size 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 32 K blocks and 32 TB for a tablespace with 8 K 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.

11g中当采用32 K块时单个表空间最大可以扩展到128 TB,而一个数据库最多拥有64 K个表空间,则可以得出单个数据库的理论最大值为128TB *64 K= 8192 PB= 8EB,该数据与Oracle 10g 数据库的容量持平,换而言之11g中数据库的容量并未增加。

Youtube视频网站一年产生的信息量大约在800TB,世界上1000强的公司所有数据库的总数据量约合1EB(平均一个公司1PB),而64位可寻址内存的最大容量为16EB,理论上我们可以把所有这些少于8EB的信息存储到您的笔记本上安装的Oracle数据库中,而且可以将它们完全缓存到内存中以供读取。

在几年前没有人相信TB级别的数据库会在不久后普及,但是我们今天可以很自信地说随着TB级别的数据库不断涌现,无论从硬件角度或者软件角度支撑该数量级的数据库的solution都已经十分成熟了。

在11g未来的日子里,我们将注目于EB级数据库的出现!

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