5.9.2  Incrementally Updating a Materialized View

You can schedule a materialized view to be regenerated on a predefined schedule by assigning a “cycle” to the view. (See Creating a Materialized View for more information.) This allows the materialized view to be updated with new data from the database. However, for a large data set, repeatedly regenerating the materialized view in its entirety may prove inefficient.

To improve performance, rather than regenerating the materialized view in its entirety, you can instead update the materialized view incrementally based on a set of specified conditions. For example, you can selectively update the materialized view with data which has posted subsequent to the previous materialization. Likewise, you can delete selected records from the materialized view if they meet a specified condition, such as an expiration date.

To specify the criteria that govern the incremental materialized view update, add the desired conditions to the MV Update tab of the Data Block in the Data Worksheet. The Data Block's MV Update condition will be tested each time an existing materialized view is regenerated (based on the cycle specified for the view), and the view regeneration will be limited to the additions and deletions specified by the condition.

See Defining a Materialized View Update Condition in Data Mashup for more information on how to define the update conditions in the MV Update tab.

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