11g materialized view refresh

 Hi,

Can Oracle 11g only refresh the columns in the mv? In other words, for the sample tables and mv below, when the data changed for column a3 or b2, which are not in the mv definition, will Oracle refresh the mv?

My problem is that the mv refreshed too many times because the base tables have many more columns not in the mv.

Here is an example:

Create table A ( a1 number not null, a2 varchar2(80), A3 DATE);

Create table B ( b1 number not null, a1 number, b2 varchar2(80), b3 DATE);

CREATE MATERIALIZED VIEW LOG ON A WITH ROWID;