A new feature in Oracle8i provided a high-speed mechanism for copying tablespaces (data files) between identical systems and allowing the same data to be accessed by both systems. Now data movement could be as fast as simply transferring the files between machines.
Transporting tablespaces is particularly useful for:
- Feeding data from OLTP systems to data warehouse staging systems
- Updating data warehouses and data marts from staging systems
- Loading data marts from central data warehouses
- Archiving OLTP and data warehouse systems efficiently
The Export and Import utilities are used to "unplug" and "plug-in" the data dictionary structural information (metadata) that pertains to the objects in the tablespace set being transported. The data is copied by operating system commands and is only limited by network bandwidth and hardware limitations. Since the Export/Import utilities only transfer the metadata, they run much faster than their more traditional counterparts.
The problem is that to "unplug" the tablespace, it had to be taken offline first. This could be a problem for applications that require 24 x 7 data availability. In 10G R2, administrators are able to create transportable tablespaces using RMAN backups instead of the online database datafiles. This allows the data to be moved without making it read only in the source database.