BIGFILE | SMALLFILE

Use this clause to determine whether the tablespace is a bigfile or smallfile tablespace. This clause overrides any default tablespace type setting for the database.

  • A bigfile tablespace contains only one data file or temp file, which can contain up to approximately 4 billion (232) blocks. The maximum size of the single data file or temp file is 128 terabytes (TB) for a tablespace with 32K blocks and 32TB for a tablespace with 8K blocks.

  • A smallfile tablespace is a traditional Oracle tablespace, which can contain 1022 data files or temp files, each of which can contain up to approximately 4 million (222) blocks.(default)

If you omit this clause, then Oracle Database uses the current default tablespace type of permanent or temporary tablespace set for the database. If you specify BIGFILE for a permanent tablespace, then the database by default creates a locally managed tablespace with automatic segment-space management.

Restriction on Bigfile Tablespaces You can specify only one data file in the DATAFILE clause or one temp file in the TEMPFILE clause.

Bigfile Tablespaces

A bigfile tablespace is a tablespace with a single, but potentially very large (up to 4G blocks) data file. Traditional smallfile tablespaces, in contrast, can contain multiple data files, but the files cannot be as large. The benefits of bigfile tablespaces are the following:

  • A bigfile tablespace with 8K blocks can contain a 32 terabyte data file. A bigfile tablespace with 32K blocks can contain a 128 terabyte data file. The maximum number of data files in an Oracle Database is limited (usually to 64K files). Therefore, bigfile tablespaces can significantly enhance the storage capacity of an Oracle Database.

  • Bigfile tablespaces can reduce the number of data files needed for a database. An additional benefit is that the DB_FILES initialization parameter and MAXDATAFILES parameter of the CREATE DATABASE and CREATE CONTROLFILE statements can be adjusted to reduce the amount of SGA space required for data file information and the size of the control file.

  • Bigfile tablespaces simplify database management by providing data file transparency. SQL syntax for the ALTER TABLESPACE statement lets you perform operations on tablespaces, rather than the underlying individual data files.

Bigfile tablespaces are supported only for locally managed tablespaces with automatic segment space management, with three exceptions: locally managed undo tablespaces, temporary tablespaces, and the SYSTEM tablespace.

Notes:

  • Bigfile tablespaces are intended to be used with Automatic Storage Management (Oracle ASM) or other logical volume managers that supports striping or RAID, and dynamically extensible logical volumes.

  • Avoid creating bigfile tablespaces on a system that does not support striping because of negative implications for parallel query execution and RMAN backup parallelization.

  • Using bigfile tablespaces on platforms that do not support large file sizes is not recommended and can limit tablespace capacity. See your operating system specific documentation for information about maximum supported file sizes.

  • Creating a Bigfile Tablespace

    To create a bigfile tablespace, specify the BIGFILE keyword of the CREATE TABLESPACE statement (CREATE BIGFILE TABLESPACE ...). Oracle Database automatically creates a locally managed tablespace with automatic segment space management. You can, but need not, specify EXTENTMANAGEMENT LOCAL and SEGMENT SPACE MANAGEMENT AUTO in this statement. However, the database returns an error if you specify EXTENTMANAGEMENT DICTIONARY or SEGMENT SPACE MANAGEMENT MANUAL. The remaining syntax of the statement is the same as for theCREATE TABLESPACE statement, but you can only specify one data file. For example:

    CREATE BIGFILE TABLESPACE bigtbs
        DATAFILE '/u02/oracle/data/bigtbs01.dbf' SIZE 50G
    ...
    

    You can specify SIZE in kilobytes (K), megabytes (M), gigabytes (G), or terabytes (T).

    If the default tablespace type was set to BIGFILE at database creation, you need not specify the keyword BIGFILE in the CREATE TABLESPACEstatement. A bigfile tablespace is created by default.

    If the default tablespace type was set to BIGFILE at database creation, but you want to create a traditional (smallfile) tablespace, then specify aCREATE SMALLFILE TABLESPACE statement to override the default tablespace type for the tablespace that you are creating.

Identifying a Bigfile Tablespace

The following views contain a BIGFILE column that identifies a tablespace as a bigfile tablespace:

  • DBA_TABLESPACES

  • USER_TABLESPACES

  • V$TABLESPACE

You can also identify a bigfile tablespace by the relative file number of its single data file. That number is 1024 on most platforms, but 4096 on OS/390.

==========================

创建BIGFILE 时,oracle 自动创建本地管理和自动段空间管理(ASSM)的表空间.
Oracle Database automatically creates a locally managed tablespace with automatic segment space management.
Use this clause to determine whether the tablespace is a bigfile or smallfile tablespace.
This clause overrides any default tablespace type setting for the database.
· A bigfiletablespace containsonly one datafile or tempfile, which can contain up to approximately 4 billion(232) blocks.大文件表空间只能包含一个数据文件或临时文件.
· A smallfiletablespace is atraditional Oracle tablespace, which can contain 1022 datafiles or tempfiles,each of which can contain up to approximately 4 million (222)blocks.
使用大文件表空间的好处:
大文件表空间可以化最小表空间文件数量,从而简化DBA 管理,在大型数据库中的表空间可能包含几十或几百个数据文件,随着文件数据的增加,一些数据库参数需要做出相应的调整比如db_files,这个静态参数还要重启数据库才能生效,这都给数据库的维护带来不便,大文件表空间可以解决这个问题.由于文件数量减少,控制文件的空间使用也随之减少,检查点等数据库内部操作需要同步的文件头数量也大大减少.

ORACLE表空间bigfile和smallfile的更多相关文章

  1. 【转】Oracle 表空间与数据文件

    --============================== --Oracle 表空间与数据文件 --============================== /* 一.概念 表空间:是一个或 ...

  2. Oracle 表空间与数据文件

    -============================== --Oracle 表空间与数据文件 --============================== /* 一.概念 表空间:是一个或多 ...

  3. Oracle表空间管理

    oracle表空间相关常用命令小结: 1.ALTER DATABASE SET DEFAULT BIGFILE TABLESPACE;              //修改表空间数据文件类型 2.ALT ...

  4. Oracle表空间详解

    Oracle表空间详解 1.表空间的分类 Oracle数据库把表空间分为两类:系统表空间和非系统表空间. 1.1系统表空间指的是数据库系统创建时需要的表空间,这些表空间在数据库创建时自动创建,是每个数 ...

  5. Oracle 表空间查询与操作方法

    一.查询篇 1.查询oracle表空间的使用情况 select b.file_id 文件ID,  b.tablespace_name 表空间,  b.file_name 物理文件名,  b.bytes ...

  6. Oracle 表空间的日常维护与管理

    目录 Oracle 表空间的日常维护与管理 1.创建数据表空间 2.创建临时表空间 3.创建 UNDO 表空间 4.表空间的扩展与修改大小 5.表空间重命名 6.表空间的删除 7.更改表空间的读写模式 ...

  7. Oracle表空间,用户,用户授权

    一:Oracle表空间 1,Oracle表空间与SQL Server文件组对比 SQL Server的文件组(文件组包括若干MDF,NDF数据文件)对我们来说并不陌生,前段时间我在博客“怎样玩转千万级 ...

  8. 六分钟学会创建Oracle表空间的步骤

    经过长时间学习创建Oracle表空间,于是和大家分享一下,看完本文你肯定有不少收获,希望本文能教会你更多东西. 1.先查询空闲空间 select tablespace_name,file_id,blo ...

  9. 修改Oracle 表空间名称 tablespace name

    修改表空间名称步骤如下: 1. 使用oracle用户登录执行 $sqlplus / as sysdba 2. 执行修改表空间命令如下 SQL> alter tablespace  TEST re ...

随机推荐

  1. node.js 包教不包会 (Windows版详解)

    针对@alsotang 的新手入门教程 https://github.com/alsotang/node-lessons ,详解该教程在Windows中的实践,包括博主在实践过程中遇到的问题及解决方案 ...

  2. 老陈 ASP.NET封装

    第一个页面 using System; using System.Collections.Generic; using System.ComponentModel; using System.Data ...

  3. Visual studio 2013 添加 GitHub

  4. angularJS Directive学习

    Directive 指令 直接上实例 index.html <!doctype html> <html ng-app="drag"> <head> ...

  5. Jquery table元素操作-创建|数据填充|重置|隐藏行

    1.Jquery创建表格 /** * 创建表格 * @param label 标题 json格式,数据结构见附录1 * @param data 数据 json格式,数据结构见附录1 * @param ...

  6. JWT(JSON Web Token) 多网站的单点登录,放弃session

    多个网站之间的登录信息共享, 一种解决方案是基于cookie - session的登录认证方式,这种方式跨域比较复杂. 另一种替代方案是采用基于算法的认证方式, JWT(json web token) ...

  7. CentOS7.2安装jdk7u80

    1.cd /usr/local 2.tar zxvf jdk-7u80-linux-x64.tar.gz 3.vi /etc/profile 4.输入i 加入内容如下: export JAVA_HOM ...

  8. u3d发送邮件

    http://gad.qq.com/article/detail/22810 https://www.douban.com/note/655356118/ http://gad.qq.com/arti ...

  9. Hibernate(9)_双向n对n

    1.概述 ①双向 n-n 关联需要两端都使用集合属性 ②双向n-n关联必须使用连接表 ③集合属性应增加 key 子元素用以映射外键列, 集合元素里还应增加many-to-many子元素关联实体类 ④在 ...

  10. Python3 下找不到urllib2的问题

    Python 3.* 用urllib.request来代替原来的urllib2,因此调用的时候改为: >>> import urllib.request >>> u ...