REFRESH MATERIALIZED VIEW
Description
REFRESH MATERIALIZED VIEW completely replaces the contents of a materialized view. The old contents are discarded. If WITH DATA is specified (or defaults) the backing query is executed to provide the new data, and the materialized view is left in a scannable state. If WITH NO DATA is specified no new data is generated and the materialized view is left in an unscannable state.
CONCURRENTLY and WITH NO DATA may not be specified together.
Parameters
- CONCURRENTLY
Refresh the materialized view without locking out concurrent selects on the materialized view. Without this option a refresh which affects a lot of rows will tend to use fewer resources and complete more quickly, but could block other connections which are trying to read from the materialized view. This option may be faster in cases where a small number of rows are affected.
This option is only allowed if there is at least one UNIQUE index on the materialized view which uses only column names and includes all rows; that is, it must not index on any expressions nor include a WHERE clause.
This option may not be used when the materialized view is not already populated.
Even with this option only one REFRESH at a time may run against any one materialized view.
- name
The name (optionally schema-qualified) of the materialized view to refresh.
Notes
While the default index for future CLUSTER operations is retained, REFRESH MATERIALIZED VIEW does not order the generated rows based on this property. If you want the data to be ordered upon generation, you must use an ORDER BY clause in the backing query.
Examples
This command will replace the contents of the materialized view called order_summary using the query from the materialized view's definition, and leave it in a scannable state:
REFRESH MATERIALIZED VIEW order_summary;
This command will free storage associated with the materialized view annual_statistics_basis and leave it in an unscannable state:
REFRESH MATERIALIZED VIEW annual_statistics_basis WITH NO DATA;