alter index的操作

(a).分配区和释放区
分配：alter index ix_my_tab allocate extent;（可以指定分配的数据文件区）
释放：alter index ix_my_tab deallocate unused (keep 100m);
(b).修改日志属性
alter index ix_my_tab logging;
alter index ix_my_tab nologging;
(c).修改存储和物理属性
alter index ix_my_tab pctfree 10 pctused 40 initrans 5 storage(next 100k maxextents unlimited freelists 10 buffer_pool keep);
(d).添加散列索引分区
alter index ix_my_tab add partition tablespace users;
(e).合并和删除分区
合并：alter index ix_my_tab coalesce partition;
删除：alter index ix_my_tab drop paratition ix_my_tab_li;
(f).更改分区
alter index ix_my_tab modify partition ix_my_tab_li allocate extent size 100m;
alter index ix_my_tab modify partition ix_my_tab_li deallocate unused keep 100m;
(g).分区重命名
alter index ix_my_tab rename partition ix_my_tab_li to ix_my_tab_li01;
(h).重建无分区索引
alter index ix_my_tab rebuild online;
(i).缩小操作
alter index ix_my_tab shrink space;
alter index ix_my_tab shrink space compact cascade;