REFRESH MATERIALIZED VIEW — replace the contents of a materialized view
REFRESH MATERIALIZED VIEW [ CONCURRENTLY ] name
    [ WITH [ NO ] DATA ]   REFRESH MATERIALIZED VIEW completely replaces the
   contents of a materialized view.  To execute this command you must be the
   owner of the 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.
  
CONCURRENTLYRefresh 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.
     
nameThe name (optionally schema-qualified) of the materialized view to refresh.
   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.
  
   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;
   REFRESH MATERIALIZED VIEW is a
   PostgreSQL extension.