Oracle 索引的使用情况查看
http://topmanopensource.iteye.com/blog/1152779

1.查询用户的索引
select index_name,table_name,tablespace_name,index_type,uniqueness,status
from dba_indexes where owner='SCOTT';

2.查询用户的索引列
select index_name,table_name,column_name, index_owner,table_owner
from dba_ind_columns
where table_owner='SCOTT';

3.查看索引的各种初始化因子
select index_name,table_name,tablespace_name,
pct_free,pct_increase,initial_extent,
next_extent, status
from dba_indexes where owner='SCOTT';

4.重建和维护索引
alter index scott.emp_ename_idx rebuild
pctfree 40
storage (next 300k);

5.查看索引segment
select segment_name,segment_type,tablespace_name,extents
from dba_segments
where owner='SCOTT'
and segment_type='INDEX';

6.给索引添加相应的extent
alter index scott.emp_ename_idx allocate extent;

7.回收索引段
alter index scott.emp_ename_idx deallocate unused;

8.合并索引碎片
alter index scott.emp_ename_idx coalesce;

9.联机重建索引：
alter index scott.emp_ename_idx rebuild online;

10标识索引的使用情况
1）.启用索引监控
alter index emp_ename_idx monitoring usage;

2）.执行相关查询
select ename,job ,sal from scott.emp where ename like 'C%';

3）.查看索引是否使用
select * from v$object_usage;

4）.禁用索引监控
alter index emp_ename_idx nomonitoring usage;