SQL> select count(*) from tb_clfb;
已用时间: 00: 00: 00.02
Statistics
----------------------
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
------解决方案--------------------
- SQL code
SQL> select * from t where rownum=1; IDX----------CNAME-------------------------------------------- 1aExecution 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
------解决方案--------------------
要有
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
------解决方案--------------------
------解决方案--------------------
- SQL code
1: 打开PL\SQL Developer工具,按F52: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