How much redo generated for a particular DB operation

column value new_val V
set verify off

select a.name, b.value
from v$statname a, v$mystat b
where a.statistic# = b.statistic#
and a.name = 'redo size';

NAME VALUE
------------------------------ ----------
redo size 153976776

exec dbms_mview.refresh( 'BIG_TABLE_MV', 'C' );

select a.name, b.value, to_char( b.value-&V, '999,999,999,999' ) diff
from v$statname a, v$mystat b
where a.statistic# = b.statistic#
and a.name = 'redo size';

NAME VALUE DIFF
------------------------------ ---------- ----------------
redo size 330108116 176,131,340