Index Usage

Hi All,

DB version is 11.2.0.2

I have enabled index monitoring usage on a index as below

SQL> alter index xxx.xxxxx_ar_01 monitoring usage;
 
Index altered.

Executed few programs and after almost an hour later i did

SQL> alter index xxx.xxxxx_ar_01 NOMONITORING USAGE;
 
Index altered.

After that could see

SQL> select count(*) from v$object_usage;
 
  COUNT(*)
----------
         0
 
1 row selected.

There is zero rows in the v$object_usage table !!! why is it so?

Baskar.l