SQL & PL/SQL

I know I can create or rebuild a non-partitioned index using parallel_clause like

alter index TEST_INDEX rebuild parallel 8;

Then, I could check the degree of parallelism by query dba_indexes, result would be 8.

select degree from dba_indexes where index_name = 'TEST_INDEX';

I can disable the parallelism by issue following statement:

alter index TEST_INDEX noparallel;

--following result would be 1

select degree from dba_indexes where index_name = 'TEST_INDEX';

But when dealing with partitioned index, I can't find any view to check the degree of parallelism.

for example, assuming TEST_INDEX_PART is a partitioned index, created with noparallel option, and have two partitions P1, P2.

--degree of the index is 1

select degree from dba_indexes where index_name = 'TEST_INDEX_PART';

--rebuild P1 in parallel 8

alter index TEST_INDEX_PART rebuild partition P1 parallel 8;

--degree of the index is still 1,

select degree from dba_indexes where index_name = 'TEST_INDEX_PART';

--rebuild P2 in parallel 4

alter index TEST_INDEX_PART rebuild partition P2 parallel 4;

--degree of the index is still 1,

select degree from dba_indexes where index_name = 'TEST_INDEX_PART';

--and I can't find valid clause to disable parallelism on these partitioned index.

so, the question is, how can I check and disable degree of parallelism of partitioned index?

Or there is no such thing for partitioned index, the parallel_clause for alter index rebuild partition is only for speed boost and won't affect execution plan at all?

Thanks in advance.