Hi,

I got the answer for my problem:

8.1.6 Data Warehousing Guide (8-20) : ON COMMIT : Can be used with
materialized views on single table aggregates and materialized views
containing joins only.

9.0.1 Data Warehousing Guide (8-26) : ON COMMIT : Can be specified as long as the materialized view is fast refreshable (in other words not complex).

The query you listed is a single table non-aggregate and should thus
be able to be ON COMMIT refreshed in 9.x but not in 8.1.x.

I'm using 8.1.7.4... Dammit !