Suboptimal query plan with connect by

   A.other_date_col IS NULL
   OR A.other_date_col >= ADD_MONTHS(TO_DATE('20180901', 'YYYYMMDD'), 1)
   )

1. Parallel execution can only be achieved if we remove the "OR" operator in the "CONNECT BY" clause (with parallel hint or object level degree > 1).
2. The query performs a full table scan of A even when we add a selective where clause on indexed column:

...
WHERE  A.date_col < ADD_MONTHS(TO_DATE('20180901', 'YYYYMMDD'), 1) AND id in (val1, val2) -- there is an existing index with id as a first column

It uses the correct index if we transform the query like this:

SELECT B.col1,

        B.col2,
        ... other columns ...
        LEVEL