SYSAUX

SYSAUX is the Oracle Database auxiliary tablespace introduced in Oracle Database 10g to reduce the load on the SYS schema by serving as a centralized repository for data and metadata used by many database components. It is created automatically when a database is created and is mandatory in modern Oracle deployments. SYSAUX is separate from the SYSTEM and SYS tablespaces and is intended to host internal components rather than user objects.

The primary purpose of SYSAUX is to store data and metadata for a number of Oracle features and options. Its exact contents vary with installed features, but it commonly includes data related to performance and workload management, such as the Automatic Workload Repository (AWR), along with metadata for other components such as data mining and text indexing. The design aims to reduce pressure on SYS and improve overall manageability by consolidating auxiliary data in a single, separate tablespace.

Administration and monitoring of SYSAUX follow standard tablespace practices. The amount of space it uses grows automatically as components accumulate data. It is managed like other tablespaces, with datafiles that can be added or extended and autoextend enabled. Administrators monitor occupancy with views such as V$SYSAUX_OCCUPANTS and DBA_TABLESPACE_USAGE_METRICS. If space becomes constrained, actions may include adjusting retention settings for certain features or resizing the SYSAUX datafiles.

Notes on usage: because SYSAUX hosts data for many optional features, its contents depend on which components are installed and active in the database. It should be treated as a system-managed resource, and direct manipulation of its components is generally avoided to prevent unintended impact on database functionality.