DBA_ACTIVITY_MVIEW

DBA_ACTIVITY_MVIEW describes materialized view activity snapshots that were recently taken by the Object Activity Tracking System (OATS).

Each row in this view represents one recently completed activity snapshot and describes the materialized view activity that occurred during the snapshot interval.

Column Datatype NULL Description
SNAP_ID NUMBER NOT NULL Activity snapshot identifier
CON_DBNAME VARCHAR2(128) NOT NULL Name of the container to which the data pertains
INSTANCE_NUMBER NUMBER NOT NULL Identifier for the instance in which the activity snapshot was taken
BEGIN_TIME TIMESTAMP(3) NOT NULL Begin time for the activity snapshot interval
END_TIME TIMESTAMP(3) NOT NULL End time for the activity snapshot interval
MVIEW_NAME VARCHAR2(128) NOT NULL Name of the materialized view for which the activity snapshot was taken
MVIEW_OWNER VARCHAR2(128) NOT NULL Owner of materialized view for which the activity snapshot was taken
USER_CLASS VARCHAR2(7)   Indicates whether the activity was performed by the RDBMS (SYS) or by a user (NON-SYS)
COMPILES NUMBER  

Number of times the materialized view was compiled

This number includes:

  • Explicit compiles performed with the SQL statement ALTER MATERIALIZED VIEW ... COMPILE

  • Automatic compiles that occurred because the structure of an underlying base table changed
REWRITES_TEXTMATCH NUMBER   Number of query rewrites that used the text match rewrite method
REWRITES_GENERAL NUMBER   Number of query rewrites that used general rewrite methods
REWRITES_PARTIAL NUMBER  

Number of query rewrites that occurred when the view was partially stale

This number includes:

  • UNION ALL operations involving rewritten queries that had one branch with the materialized view and the other branch with its underlying base tables (partial rewrites)

  • Single query block rewrites of the materialized view that involved a join back to its underlying base table
REWRITES_DELTA NUMBER   Number of query rewrites that used stale data in the materialized view plus the delta information stored in the materialized view logs
REWRITES_PCT NUMBER   Number of partition change tracking (PCT) rewrites
REWRITES_HINTED NUMBER   Number of query rewrites that occurred because the materialized view was eligible for query rewrite and the SELECT statement contained the REWRITE hint with the name of the materialized view specified in the hint
NOREWRITES_HINTED NUMBER   Reserved for future use
NOREWRITES_STALE NUMBER   Number of query executions that did not use query rewrite because the materialized view was eligible for query rewrite, but stale
REFRESHES_ON_DEMAND NUMBER  

Number of ON DEMAND refreshes

This type of refresh is performed on materialized views that use the ON DEMAND refresh mode, which instructs the database to refresh the materialized view only when a manual refresh is launched by one of the three DBMS_MVIEW refresh procedures.

REFRESHES_ON_COMMIT NUMBER  

Number of ON COMMIT refreshes

This type of refresh is performed on materialized views that use the ON COMMIT refresh mode, which instructs the database to refresh the materialized view whenever the database commits a transaction that operates on a master table of the materialized view.

REFRESHES_ON_STATEMENT NUMBER  

Number of ON STATEMENT refreshes

This type of refresh is performed on materialized views that use the ON STATEMENT refresh mode, which instructs the database to perform an automatic refresh of the materialized view every time a DML operation is performed on any of the view's base tables.

REFRESHES_SCHEDULED NUMBER   Number of scheduled refreshes
REFRESHES_AUTOMATIC NUMBER   Number of automatic refreshes
REFRESHES_FAST NUMBER   Number of incremental refreshes
REFRESHES_COMPLETE NUMBER   Number of full refreshes
REFRESHES_PCT NUMBER   Number of partition change tracking (PCT) refreshes

Note: The counts in this view are approximate in order to keep system overhead low. Also, there are database activities, such as statistics collection, query compilation, and query optimization, that may cause the counts to be different than expected or to vary slightly across successive queries.

See Also: “V$ACTIVITY_MVIEW” to view in-progress materialized view activity snapshots