SQL> select count(*) from tb_clfb;已用时间: 00: 00: 00.02Statistics
----------------------------------------------------------
0 recursive calls
0 db block gets
1112 consistent gets
643 physical reads
0 redo size
375 bytes sent via SQL*Net to client
503 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
1 rows processed
----------------------------------------------------------
0 recursive calls
0 db block gets
1112 consistent gets
643 physical reads
0 redo size
375 bytes sent via SQL*Net to client
503 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
1 rows processed
SQL> select * from t where rownum=1; IDX
----------
CNAME
--------------------------------------------------------------------------------
1
aExecution Plan
----------------------------------------------------------
0 SELECT STATEMENT Optimizer=CHOOSE
1 0 COUNT (STOPKEY)
2 1 TABLE ACCESS (FULL) OF 'T'
Statistics
----------------------------------------------------------
0 recursive calls
0 db block gets
0 consistent gets
0 physical reads
0 redo size
0 bytes sent via SQL*Net to client
0 bytes received via SQL*Net from client
0 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
1 rows processed
Execution Plan
----------------------------------------------------------
0 SELECT STATEMENT Optimizer=CHOOSE
1 0 COUNT (STOPKEY)
2 1 TABLE ACCESS (FULL) OF 'T'
才能看得出,
你是不是用的set autotrace on statistics这样看不到 Plan
直接set autotrace on看看信息
SP2-0613: 无法验证 PLAN_TABLE 格式或实体
SP2-0611: 启用EXPLAIN报告时出错
到网上google一下,很多step by step 安装执行计划的例子
2:SET AUTOTRACE TRACEONLY; -- 安装执行计划 FYI: http://www.eygle.com/faq/AutoTrace.htm如果想强制使用索引:-- 查索引NAME:
SQL> SELECT TABLE_NAME,
2 INDEX_NAME
3 FROM ALL_INDEXES
4 WHERE TABLE_OWNER = UPPER('SCOTT')
5 AND TABLE_NAME = UPPER('EMP');TABLE_NAME INDEX_NAME
------------------------------ ------------------------------
EMP PK_EMPSQL> SELECT /*+ INDEX(EMP PK_EMP)*/ EMPNO,ENAME
2 FROM EMP
3 WHERE EMPNO >= '7782';EMPNO ENAME
----- ----------
7782 CLARK
7788 SCOTT
7839 KING
7844 TURNER
7876 ADAMS
7900 JAMES
7902 FORD
7934 MILLER8 rows selected
执行计划安装了,我的表也有索引,但是从执行结果来看,是不是没有走索引?
SQL> select /*index(tb_clfb,inde_tb_clfb)*/ count(*) from tb_clfb; COUNT(*)
----------
0已用时间: 00: 00: 00.03Execution Plan
----------------------------------------------------------
0 SELECT STATEMENT Optimizer=CHOOSE
1 0 SORT (AGGREGATE)
2 1 TABLE ACCESS (FULL) OF 'TB_CLFB'
Statistics
----------------------------------------------------------
0 recursive calls
0 db block gets
1112 consistent gets
1110 physical reads
0 redo size
375 bytes sent via SQL*Net to client
503 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
1 rows processed
刚才写错了,少个+,现在好了,谢谢SQL> select /*+index(tb_clfb,inde_tb_clfb)*/ count(*) from tb_clfb where cc='43041'; COUNT(*)
----------
14已用时间: 00: 00: 00.01Execution Plan
----------------------------------------------------------
0 SELECT STATEMENT Optimizer=CHOOSE (Cost=2 Card=1 Bytes=12)
1 0 SORT (AGGREGATE)
2 1 INDEX (RANGE SCAN) OF 'INDE_TB_CLFB' (NON-UNIQUE) (Cost=
2 Card=907 Bytes=10884)
Statistics
----------------------------------------------------------
36 recursive calls
0 db block gets
7 consistent gets
0 physical reads
0 redo size
376 bytes sent via SQL*Net to client
503 bytes received via SQL*Net from client
2 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
1 rows processed