I created a materialized view (which I will call THE_MATERIALIZED_VIEW) with 47 million records (and with NOLOGGING, BUILD IMMEDIATE, REFRESH COMPLETE WITH PRIMARY KEY), and it took 19 minutes to complete.
However, when I executed DBMS_MVIEW.REFRESH('THE_MATERIALIZED_VIEW', 'C'), it took over an hour.
Is there something obvious that I am missing that would speed this refresh up?
(Besides trying a "fast refresh" - the materialzed view is meant to be refreshed only after the underlying tables are truncated and rebuilt.)
If it's a case of "it would help if we saw the query", let me know - I didn't include it at first as it's long.