oracle 資料檔案（Datafile ）大小限制說明

先看Oracle 官網的說明, 看的是Oracle 10gR2的文件：

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 2^22 - 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 25,000 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 2^22 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 statement Control 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 ( 2^32 ) 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 (2^22) blocks.
External Tables file	Maximum size	Dependent on the operating system. An external table can be composed of multiple files.

每個資料檔案最多隻能包含2^22-1個資料塊。這個限制是由於Oracle的Rowid中使用22位來代表Block號，這22位最多隻能代表2^22-1個資料塊。這個限制也就直接導致了每個資料檔案的最大允許大小。

在2K Block size下，資料檔案最大隻能達到約8G；

在8K Block size 下， 資料檔案最大隻能達到約4*8G；

在32K Block size下，資料檔案最大隻能達到約16*8G。.

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.

Bigfile tablespace 只允許一個資料檔案,在大檔案表空間下，Oracle使用32位來代表Block號， 每個檔案最多可以容納4G（2^32）個Block。那麼也就是說當Block_size為2k時，資料檔案可以達到8T。當Block_size為8k時，資料檔案可以達到32T。當block_size 為32K時，資料檔案可以達到128T。

一般不建議把單個資料檔案建的太大。 因為太大的話，如果某個資料檔案出現問題，恢復起來費時較長。

一般都是把單個資料檔案設成8G一個，如果表空間較大的話，可以多弄幾個資料檔案。 在上面的表格裡也提到了。 單個表空間最大支援1022個資料檔案。所以資料檔案是絕對夠用的。

oracle 資料檔案（Datafile ） 大小 限制 說明

oracle 資料檔案（Datafile ） 大小 限制 說明

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oracle 資料檔案（Datafile ）大小限制說明

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