1 说明

在12.2中引入了一个新的概念“本地临时表空间”,而之前版本中的临时表空间则被称为“共享临时表空间”。

当很多read-only实例访问一个数据库时,本地临时表空间可以提高涉及到排序查询的性能。

共享的临时表空间在共享磁盘上存储临时文件,以便所有数据库实例都可以访问临时表空间。相反,本地临时表空间为每个数据库实例存储单独的、非共享的临时文件。本地临时表空间对于Oracle Real Application Clusters 或 Oracle Flex Clusters很有用。

可以在read-only和read/write数据实例上创建本地临时表空间。

临时表空间优点:

1. Improving I/O performance

2. Avoiding expensive cross-instance temporary space management

3. Improving instance startup performance

 

2 本地临时表空间和共享临时表空间对比

Shared Temporary Tablespace

Local Temporary Tablespace

Created with the CREATE TEMPORARY TABLESPACEstatement.

Created with the CREATE LOCAL TEMPORARY TABLESPACE statement.

Note: A local temporary tablespaces is always a ​bigfile tablespace​, but the BIGFILE keyword is not required in the creation statement.

Creates a single temporary tablespace for the database.

Creates separate temporary tablespaces for every database instance. The FOR LEAF option creates tablespaces only for read-only instances. The FOR ALL option creates tablespaces for all instances, both read-only and read/write.

Supports tablespace groups.

Does not support tablespace groups.

Stores temp file metadata in the control file.

Stores temp file metadata common to all instances in the control file, and instance-specific metadata (for example, the bitmaps for allocation, current temp file sizes, and file status) in the SGA.

3 具体例子

---创建本地临时表空间,和创建普通临时表空间没什么区别,多了一个关键字“local”和“FOR ALL or FOR LEAF”

SQL> CREATE LOCAL TEMPORARY TABLESPACE FOR ALL cndba_local_temp
TEMPFILE '/u01/app/oracle/oradata/orcl/cndba_local_temp01.dbf' SIZE 5M AUTOEXTEND ON;

Tablespace created.

1 说明

在12.2中引入了一个新的概念“本地临时表空间”,而之前版本中的临时表空间则被称为“共享临时表空间”。

当很多read-only实例访问一个数据库时,本地临时表空间可以提高涉及到排序查询的性能。

共享的临时表空间在共享磁盘上存储临时文件,以便所有数据库实例都可以访问临时表空间。相反,本地临时表空间为每个数据库实例存储单独的、非共享的临时文件。本地临时表空间对于Oracle Real Application Clusters 或 Oracle Flex Clusters很有用。

可以在read-only和read/write数据实例上创建本地临时表空间。

临时表空间优点:

1. Improving I/O performance

2. Avoiding expensive cross-instance temporary space management

3. Improving instance startup performance

 

2 本地临时表空间和共享临时表空间对比

Shared Temporary Tablespace

Local Temporary Tablespace

Created with the CREATE TEMPORARY TABLESPACEstatement.

Created with the CREATE LOCAL TEMPORARY TABLESPACE statement.

Note: A local temporary tablespaces is always a ​bigfile tablespace​, but the BIGFILE keyword is not required in the creation statement.

Creates a single temporary tablespace for the database.

Creates separate temporary tablespaces for every database instance. The FOR LEAF option creates tablespaces only for read-only instances. The FOR ALL option creates tablespaces for all instances, both read-only and read/write.

Supports tablespace groups.

Does not support tablespace groups.

Stores temp file metadata in the control file.

Stores temp file metadata common to all instances in the control file, and instance-specific metadata (for example, the bitmaps for allocation, current temp file sizes, and file status) in the SGA.

3 具体例子

---创建本地临时表空间,和创建普通临时表空间没什么区别,多了一个关键字“local”和“FOR ALL or FOR LEAF”

SQL> CREATE LOCAL TEMPORARY TABLESPACE FOR ALL cndba_local_temp
TEMPFILE '/u01/app/oracle/oradata/orcl/cndba_local_temp01.dbf' SIZE 5M AUTOEXTEND ON;

Tablespace created.