
The Data Dictionary
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Log group views
A log group is used to multiplex standby log files across dif-
ferent locations, for the purpose of reducing the impact of a
disk failure disaster on the recovery process. The following
views provide information about log groups:
Materialized view views
A materialized view is a view that is used to speed up data
warehouse queries with precalculated aggregates. The fol-
lowing views provide information about materialized views:
Networking and distributed transaction views
The following views provide information about the status of
Oracle networking, remote databases, and distributed trans-
actions to these remote databases:
*_LOCKS
Lists all locks held or requested in the database.
*_WAITERS
Lists all sessions that are waiting on a lock held by
another session.
DBMS_LOCK_ALLOCATED
Shows which locks the current user has allocated.
*_LOG_GROUPS
Lists the tables that are associated with log groups.
*_LOG_GROUP_COLUMNS
Lists the columns assigned to log groups.
*_BASE_TABLE_MVIEWS
Lists information about existing materialized views.
*_MVIEW_LOGS
Lists information about materialized view logs, which
track changes to the master tables that can be used to
refresh the materialized views.
*_2PC_NEIGHBORS
Contains information about the commit point for
distributed transactions listed in *_2PC_PENDING.
*_2PC_PENDING
Lists information about distributed transactions
requiring recovery.