In the Enterprise Manager Console home page, often the alert arises "N objects are invalid in XXX schema".
When i go to that objects, they are materialized views and it says "Need recompile" . Most of the "invalid state" is disappears after recompile. However one of them is always invalid. After sometimes others are becoming invalid again. Strange thing is that these materialized views are working fine and the refresh times are correct. I mean there is no refreshing problem. Do you have any idea why the enterprise manager calls them invalid?