d.
ORACLE instance shut down.
SYS@ORCL>startup
ORACLE instance started.
Total System Global Area 285212672 bytes
Fixed Size 1218992 bytes
Variable Size 71304784 bytes
Database Buffers 209715200 bytes
Redo Buffers 2973696 bytes
Database mounted.
Database opened.
SYS@ORCL>conn tyger/tyger
Connected.
TYGER@ORCL>show parameter query
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
query_rewrite_enabled string TRUE
query_rewrite_integrity string STALE_TOLERATED
TYGER@ORCL>set autot traceonly explain
TYGER@ORCL>select count(*) from emp;
Execution Plan
----------------------------------------------------------
Plan hash value: 2083865914
-------------------------------------------------------------------
| Id | Operation | Name | Rows | Cost (%CPU)| Time |
-------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 3 (0)| 00:00:01 |
| 1 | SORT AGGREGATE | | 1 | | |
| 2 | TABLE ACCESS FULL| EMP | 14 | 3 (0)| 00:00:01 |
-------------------------------------------------------------------
Note
-----
- dynamic sampling used for this statement
虽然结果有点不是很满意，但是看完后基本可以了解 query_rewrite_integrity 这个参数了吧
遗留问题：356 行 stale_tolerated 参数设置， 如果看出错误的步骤 欢迎指正。
|