[Oracle]-[索引][HINT][执行计划]-带HINT的索引执行计划(二)
TE | | 1 | | |
| 2 | TABLE ACCESS FULL| TBL_SMALL | 3 | 2 (0)| 00:00:01 |
------------------------------------------------------------------------
Note
-----
- dynamic sampling used for this statement
SQL> select count(id) from tbl_small;
Execution Plan
----------------------------------------------------------
Plan hash value: 1539159417
----------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
----------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 13 | 1 (0)| 00:00:01 |
| 1 | SORT AGGREGATE | | 1 | 13 | | |
| 2 | INDEX FULL SCAN| T_S_IDX | 3 | 39 | 1 (0)| 00:00:01 |
----------------------------------------------------------------------------
Note
-----
- dynamic sampling used for this statement
SQL> select /*+ index(tbl_small, t_s_idx) */ count(*) from tbl_small;
Execution Plan
----------------------------------------------------------
Plan hash value: 1452584873
------------------------------------------------------------------------
| Id | Operation | Name | Rows | Cost (%CPU)| Time |
------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 2 (0)| 00:00:01 |
| 1 | SORT AGGREGATE | | 1 | | |
| 2 | TABLE ACCESS FULL| TBL_SMALL | 3 | 2 (0)| 00:00:01 |
------------------------------------------------------------------------
Note
-----
- dynamic sampling used for this statement
SQL> select /*+ index(tbl_small, t_s_idx) */ count(id) from tbl_small;
Execution Plan
----------------------------------------------------------
Plan hash value: 1539159417
----------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
----------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 13 | 1 (0)| 00:00:01 |
| 1 | SORT AGGREGATE | | 1 | 13 | | |
| 2 | INDEX FULL SCAN| T_S_IDX | 3 | 39 | 1 (0)| 00:00:01 |
----------------------------------------------------------------------------
Note
-----
- dynamic sampling used for this statement
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
TBL_BIG表：
SQL> select count(*) from tbl_big;
Execution Plan
----------------------------------------------------------
Plan hash value: 475686685
----------------------------------------------------------------------
| Id | Operation | Name | Rows | Cost (%CPU)| Time |
----------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 3 (0)| 00:00:01 |
| 1 | SORT AGGREGATE | | 1 | | |
| 2 | TABLE ACCESS FULL| TBL_BIG | 1000 | 3 (0)| 00:00:01 |
----------------------------------------------------------------------
Note
-----
- dynamic sampling used for this stateme