How to find which queries is using which indexes

Question

So, I have a db 11gr2 and many indexes. Since I would like to delete some of them, I could see which indexes are unused, but I would like to see if some of indexes are used ony by one or two queries...
how could I found that?

Answer 1

If you have license for AWR views, use the below sql to identify indexes used.
This script has following bind variable
a1: owner
a and b: begin and end of snapshot
a2: tablespace name where your index exists
As suggested in this thread, do not plan to drop Foriegn key indexes if they are not listed.
col object_name for a30
col tablespace_anme fora 12
col count for 9999
col operation for a35
col options for a25
set lines 160
select c.*, d.tablespace_name
from (select
a.object_name ,
a.operation ,
a.options ,
count(1)
from
dba_hist_sql_plan a,
dba_hist_sqlstat b
where
a.object_owner ='&a1'
and
a.operation like '%INDEX%'
and
a.sql_id = b.sql_id
and b.snap_id between &a and &b
group by
a.object_name,
a.operation,
a.options
order by
4 desc) c,
dba_segments d
where c.object_name=d.segment_name
and d.tablespace_name='&a2'