Partitioning

Partitioning addresses the key problem of supporting very large tables and indexes by allowing users to decompose them into smaller and more manageable pieces called partitions. All partitions of a table or index have the same logical attributes, although their physical attributes can be different. For example, all partitions in a table share the same column and constraint definitions; and all partitions in an index share the same index columns. However, storage specifications and other physical attributes such as PCTFREE, PCTUSED, INITRANS, and MAXTRANS can vary for different partitions of the same table or index. Each partition is stored in a separate segment. Optionally, you can store each partition in a separate tablespace, which has the following advantages:
You can contain the impact of damaged data.
You can back up and recover each partition independently.
You can balance I/O load by mapping partitions to disk drives.