Optimizing SQL for views on views

Question

i'm trying to optimize the performance of a view, which joins 2
other views:
select *
from v1, v2
where v2.xxx = v1.xxx
when i select data from the view, i set a where clause that
results in only one matching row in the view v1 that can be
accessed by rowid (unique index). There is also a (none-unique)
index on the column xxx of that v2 view which should by used by
the optimizer (rule-based, 7.3.4.3.0).
But it isn't. Instead the database performs a full table scan of
the driving table of the v2 view, finds some rows and merges the
data with those from the v1 view. But as the v2 view is very
large it takes very long....
When i type
select * from v2 where xxx='abc'
the query executes qickly because the index on xxx is used.
What can prevent the optimizer from using the index on xxx in my
view?
I even tried to force use of the index by the INDEX hint but it
didn't work.
any help appreciated
thanks
null

Answer 1

Thanks kgronau,
My Oracle gateway for SQL server is in a Linux box and obviously the SQL server in a windows box.
In that case how I would execute dg4msql_cvw.sql which is under $ORACLE_HOME/dg4msql/admin path of Linux server?
Regards
Satish