Materialized View Refresh

Oracle Database Materialized View Refresh:
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Refresh Option:
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COMPLETE
C
Refreshes by recalculating the materialized view's defining query when atomic refresh=TRUE and COMPLETE is the same as FORCE if atomic refresh=FALSE.
FAST
F
Refreshes by incrementally applying changes to the detail tables.
FORCE
?
Uses the default refresh method. If the default refresh method is FORCE, it tries to do a fast refresh. If that is not possible, it does a complete refresh.
ALWAYS
A
Unconditionally does a complete refresh.

Refresh operations:
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DBMS_MVIEW.REFRESH
Refresh one or more materialized views.

DBMS_MVIEW.REFRESH_ALL_MVIEWS
Refresh all materialized views.

DBMS_MVIEW.REFRESH_DEPENDENT
Refresh all table-based materialized views that depend on a specified detail table or list of detail tables.

Required Initialization Parameters for Warehouse Refresh:
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JOB_QUEUE_PROCESSES
The number of background processes. Determines how many materialized views can be refreshed concurrently.

JOB_QUEUE_INTERVAL
In seconds, the interval between which the job queue scheduler checks to see if a new job has been submitted to the job queue.

UTL_FILE_DIR
Determines the directory where the refresh log is written. If unspecified, no refresh log will be created

Note:These packages also create a log which, by default, is called refresh.log and is useful in helping to diagnose problems during the refresh process. This log file can be renamed by calling the procedure DBMS_OLAP.SET_LOGFILE_NAME ('log filename').

DBMS_SNAPSHOT
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DBMS_SNAPSHOT enables you to refresh snapshots that are not part of the same refresh group and purge logs.

Note: DBMS_MVIEW is a synonym for DBMS_SNAPSHOT. This synonym may be used in the future with data warehousing.

Examples:
Complete Refresh:
SQL> execute DBMS_SNAPSHOT.REFRESH( 'MV_EMP','c');
PL/SQL procedure successfully completed.

Fast Refresh
SQL> execute DBMS_SNAPSHOT.REFRESH( 'MV_EMP','f');
PL/SQL procedure successfully completed.

Force Refresh
SQL> execute DBMS_SNAPSHOT.REFRESH( 'MV_EMP','?');
PL/SQL procedure successfully completed.

Also provided with DBMS_SNAPSHOT is the REFRESH_ALL procedure. This procedure refreshes all materialized views, which were defined using the automatic refreshes.
SQL> execute DBMS_SNAPSHOT.REFRESH_ALL;
PL/SQL procedure successfully completed.