Oracle lets you create bigfile tablespaces. This allows Oracle Database to contain
tablespaces made up of single large files rather than numerous smaller ones. This lets
Oracle Database utilize the ability of 64-bit systems to create and manage ultralarge
files. The consequence of this is that Oracle Database can now scale up to 8 exabytes in
size.
ORACLE让你创建大文件表空间。这个允许ORACLE数据库包含表空间由单独大文件
组成好过于多个小文件。它可以让ORACLE使用64位系统能力去创建和管理超大文件。
这个的意义在于ORACLE现在容量可以扩大到8000000TB大小。
With Oracle-managed files, bigfile tablespaces make datafiles completely transparent
for users. In other words, you can perform operations on tablespaces, rather than the
underlying datafile. Bigfile tablespaces make the tablespace the main unit of the disk
space administration, backup and recovery, and so on. Bigfile tablespaces also simplify
datafile management with Oracle-managed files and Automatic Storage Management
by eliminating the need for adding new datafiles and dealing with multiple files.
基于ORACLE-管理文件，大文件表空间使得文件完全透明的对于用户。换句话说你可
以执行操作在表空间上而不需要底层的数据文件。大文件表空间使得表空间成为磁盘
空间管理，备份恢复等的主要单元。大文件表空间也简化了基于ORACLE-管理和ASM
的数据文件管理。不需要添加新文件和处理多个文件。
The system default is to create a smallfile tablespace, which is the traditional type of
Oracle tablespace. The SYSTEM and SYSAUX tablespace types are always created using
the system default type.
系统默认创建小文件表空间。它是ORACLE的传统的表空间类型。SYSTEM和SYSAUX表
空间通常创建使用系统默认类型。
Bigfile tablespaces are supported only for locally managed tablespaces with automatic
segment-space management. There are two exceptions: locally managed undo and
temporary tablespaces can be bigfile tablespaces, even though their segments are
manually managed.
大文件表空间仅支持本地管理的表空间使用自动段的管理方式。有两种意外：本地管理UNDO
和临时表空间可以是大文件表空间。尽管它们的段是手工管理的。
An Oracle database can contain both bigfile and smallfile tablespaces. Tablespaces of
different types are indistinguishable in terms of execution of SQL statements that do
not explicitly refer to datafiles.
一个ORACLE数据库可以包含大文件和小文件表空间。不同类型的表空间在执行SQL的
条件上是没有区别的，那些SQL没有明确的与数据文件有关。
You can create a group of temporary tablespaces that let a user consume temporary
space from multiple tablespaces. A tablespace group can also be specified as the
default temporary tablespace for the database. This is useful with bigfile tablespaces,
where you could need a lot of temporary tablespace for sorts.
你可以创建一组临时表空间，让用户从多个表空间去使用临时空间。一个表空间组
也可以被指定作为默认的临时表空间。使用大文件表空间是有好处的，你可以需求大量
的临时表空间用于排序。
Benefits of Bigfile Tablespaces
■ Bigfile tablespaces can significantly increase the storage capacity of an Oracle
database. Smallfile tablespaces can contain up to 1024 files, but bigfile tablespaces
contain only one file that can be 1024 times larger than a smallfile tablespace. The
total tablespace capacity is the same for smallfile tablespaces and bigfile
tablespaces. However, because there is limit of 64K datafiles for each database, a
database can contain 1024 times more bigfile tablespaces than smallfile
tablespaces, so bigfile tablespaces increase the total database capacity by 3 orders
of magnitude. In other words, 8 exabytes is the maximum size of the Oracle
database when bigfile tablespaces are used with the maximum block size (32 k).
#大文件表空间可以明显增加ORACLE数据库的容量。小文件表空间可以最多包含的1024
个文件，但大文件表空间仅一个文件可以1024倍大于一个小文件表空间。总的表空间容量
包含大文件和小文件表空间。但是因为对于每个数据库有64K个数据文件的限制，一个数据
库可以包含1024倍于小文件的大文件表空间。所以大文件表空间增加了总数据库的容量1000
倍的订单位级别。换而言之，8E是ORACLE数据库的最大容量当大文件表空间使用最大块的尺
寸是你32K大小。
■ Bigfile tablespaces simplify management of datafiles in ultra large databases by
reducing the number of datafiles needed. You can also adjust parameters to reduce
the SGA space required for datafile information and the size of the control file.
#大文件表空简化了数据文件的管理在超大的数据库中，通过减少所需的数据文件
数。你也可以调整参数去减少SGA空间需求对于数据文件的信息和控制文件的大小。
■ They simplify database management by providing datafile transparency.
Considerations with Bigfile Tablespaces
它们简化了数据库管理通过提供数据文件的透明度。使用大文件表空间的可信度。
■ Bigfile tablespaces are intended to be used with Automatic Storage Management
or other logical volume managers that support dynamically extensible logical
volumes and striping or RAID.
#大文件表空间可使用ASM或者其它逻辑卷管理，它支持动态扩展逻辑卷和条带化
或者是RAID
■ Avoid creating bigfile tablespaces on a system that does not support striping
because of negative implications for parallel execution and RMAN backup
parallelization.
可以避免创建大文件表空间在一个系统上，这个系统不支持条带因为负面的影响对于
并行执行和RMAN备份的并行化。
■ Avoid using bigfile tablespaces if there could possibly be no free space available
on a disk group, and the only way to extend a tablespace is to add a new datafile
on a different disk group.
避免使用大文件表空间如果它可能没有空间可用的空间在一个磁盘组上，并且只能
通过添加一个新的数据文件在一个不同的磁盘组上来扩容。
■ Using bigfile tablespaces on platforms that do not support large file sizes is not
recommended and can limit tablespace capacity. Refer to your operating system
specific documentation for information about maximum supported file sizes.
使用大文件表空间所在的平台，它不支持大文件大小的，这种情况不建议使用并且
可能会限制表空间容量。涉及到你的操作系统指定的文档关于支持最大文件尺寸
的信息。
■ Performance of database opens, checkpoints, and DBWR processes should
improve if data is stored in bigfile tablespaces instead of traditional tablespaces.
However, increasing the datafile size might increase time to restore a corrupted file
or create a new datafile.
#数据库的打开，检查点，和DBWR进程将提高性能，如果数据存储在大文件表空间
用它来代替传统的表空间。但是增加数据文件的大小可以增加恢复一个损坏文件的时间表
或者是创建一个新的文件。
