Watch Out Materialized View Refresh Group

In the post Refresh an Oracle Materialized View, we add a materialized view to a refresh group to be refreshed. When we drop the materialized view, it will be removed from the refresh group. Thus if we drop and then recreate the same materialized view, it will not be refreshed according to the schedule defined in the refresh group. We have to manually add the materialized view back to the refresh group. So I normally do not use refresh group. Instead, I create a procedure to refresh the materialized view using dbms_mview.refresh.

create or replace procedure proc_all(md varchar2 default NULL)
is
begin
 dbms_mview.refresh('MV_A');
 dbms_mview.refresh('MV_B');
 dbms_mview.refresh('MV_C');
 dbms_mview.refresh('MV_D');
end;

Then I use DBMS_SCHEDULER to schedule the job.

BEGIN
  DBMS_SCHEDULER.create_job (
    job_name        => 'my_proc',
    job_type        => 'PLSQL_BLOCK',
    job_action      => 'BEGIN proc_all; END;',
    start_date      => SYSTIMESTAMP,
    repeat_interval => 'freq=daily; byhour=19;',
    end_date        => NULL,
    enabled         => TRUE,
    comments        => 'daily job.');
END;
/