The SYSTEM tablespace contains Oracle system metadata, or the data about the data. Metadata contains table structures including column names, lengths, and datatypes, among many other things. The SYSAUX tablespace is new to Oracle Database 10g, containing various tool and utility objects such as for Recovery Manager (RMAN). Generally, data (DATA) and index (INDEX) tablespaces are split as shown in Figure 3.10 because tables and indexes are usually scanned at the same time. The UNDO tablespace contains data for undoing of transactions already executed plus providing flashback capability. The TEMP tablespace is specially formatted for fast on-disk sorting when memory capacity is exceeded for a sort. Temporary sort space is used for other functions as well, such as consistent exports. Partition tablespaces are both logically and physically split into chunks, where separate chunks can be accessed individually or as multiple groups executed in parallel.
The Controlfile, redo, and archive logs shown in Figure 3.10 are described in the next section.