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

重建和维护索引

alter index scott.emp_ename_idx rebuild
pctfree 40
storage (next 300k);

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

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

回收索引端
alter index scott.emp_ename_idx deallocate unused;
合并索引碎片
alter index scott.emp_ename_idx coalesce;

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

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;