Donald K. Burleson
SYSTEM. Contains files owned by the
SYS and SYSTEM user.
TOOLS. Contains files usually owned by SYSTEM but that apply to the
Oracle developer’s toolset; these files contain base information and
details of forms, reports, and menus.
ROLLBACK. Contains the private rollback segments; its size will
depend on number of rollback segments and expected transaction size.
May also be an Oracle-configured UNDO tablespace, which means you
will also have to plan for how long UNDO data should be retained to
allow for flashback query.
DEFAULT USER. Tablespace in which users can create and destroy
temporary, nonapplication-related tables such as those used in
SQL*REPORT for intermediate queries.
TEMPORARY USER. Tablespace for sorts, joins, and other operations
that require temporary disk space for intermediate operations. If
this tablespace is not available, and default tablespace is not set
for each user, these tables will be created and dropped in the
SYSTEM tablespace, resulting in fragmentation. Additionally, a
poorly designed join or overly ambitious SELECT statement could
result in filling the SYSTEM area and halting the database.
UNDOTBS. IN Oracle databases created from default templates in the
Database Creation Assistant (DBCA) rollback segments are placed in
the UNDO tablespace and are now referred to as UNDO segments. Oracle
uses automated management of these UNDO segments by default. This
UNDOTBS is used by Oracle to hold UNDO segments.
This is an
excerpt by Mike Ault’s book “Oracle
Administration & Management”. If you want more current Oracle tips
by Mike Ault, check out his new book “Mike
Ault’s Oracle Internals Monitoring & Tuning Scripts” or
Ault’s Oracle Scripts Download.
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Burleson. All rights reserved.
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of Oracle Corporation.