Efficient Data Refresh with Oracle Materialized Views Updates（oracle刷新物化视图）

Materialized Views, a feature of Oracle Database, is a powerful tool for efficiently refreshing data, as well as providing the related benefits of data aggregation and summarization. With increasing demands on the performance and scalability of data-driven applications, Materialized Views have become an invaluable part of optimizing data queries.

In Oracle Database, Materialized Views provide the ability to pre-compute query results and store it for use later. When the data changes in the base table, the Materialized Views that depend on it need to be updated as well. This requires executing update statements which can significantly increase the load on the database, and can lead to performance issues. However, Oracle offers efficient solutions to refresh Materialized Views using several different techniques.

The first refresh method is the Fast Refresh feature. Fast Refresh is a type of refresh that applies only to changes made in the base table. By identifying only the changes to the base table, Oracle Database can make certain optimizations that reduce the amount of work necessary to refresh the Materialized View. This reduces the duration of the refresh process and also lowers the resource utilization. This can be enabled with the QUERY REWRITE option for the Materialized View.

Oracle also provides the Complete Refresh feature for refreshing Materialized Views. This refreshes the entire Materialized View with the most up-to-date data. A Complete Refresh can be necessary for critical business applications where up-to-date data is important, such as financial reporting applications. This can be enabled with the REFRESH COMPLETE option for the Materialized View.

In addition to manual refreshes, Materialized Views can also be refreshed automatically using the automatic refresh feature. This feature can be configured using the DBMS_MVIEW.REFRESH procedure. A schedule is then defined on which the refresh will occur. Using this feature helps to ensure that the data in the Materialized Views is always up to date and helps to improve the performance of the applications.

Finally, Oracle also provides a specialized refresh technique specific to PARTITIONING by reversing the partitioning method. This is especially useful when dealing with large tables. With the REVERSE option of Oracle Database, a partitioned table is converted into a non-partitioned table prior to refresh. Once the refresh is complete, the table is converted back to a partitioned table. This can significantly reduce the refresh time, since the time required for refresh of a non-partitioned table is generally much less than for a partitioned table.

With the various methods Oracle provides for efficiently refreshing Materialized Views, applications can be assured of more up-to-date data and improved performance.

–模拟代码

BEGIN

— Refresh the entire view

DBMS_MVIEW.REFRESH(

atomic_refresh => FALSE,

refresh_mode => dbms_mview.complete);

END;