ORACLE SQL优化 ORACLE执行计划

Last login: Mon Feb  8 14:13:19 2010 from 192.168.1.249
ipnet
-bash-3.00$
-bash-3.00$ ipnet
-bash: ipnet: command not found
-bash-3.00$ su - oracle
Password:
eastcsu: incorrect password
-bash-3.00$ eastcom
-bash: eastcom: command not found
-bash-3.00$ su - oracle
Password:
[oracle@ipnet-td2 ~]$
[oracle@ipnet-td2 ~]$ sqlplus /nolog
SQL*Plus: Release 10.2.0.1.0 - Production on Mon Feb 8 14:14:08 2010
Copyright (c) 1982, 2005, Oracle.  All rights reserved.
SQL> su^H^H^H
SP2-0042: unknown command " - rest of line ignored.
SQL> conn ipnet/ipnet1234@ORAC^H^H^H
ERROR:
ORA-12154: TNS:could not resolve the connect identifier specified
SQL> ^[[A^H               " - rest of line ignored.
SQL> 042: unknown command "
SQL> conn ipnet/ipnet1234@ORCL
Connected.
SQL> set timn^H
SP2-0158: unknown SET option "tim"
SQL> set timing on
SQL> set autot traceonly
SQL> select v.NAME_CN from vendor v, vendordevicetype vt, devicetype t where t.name = vt.device_type_name and v.name = vt.vendor_name and t.name_cn = '防火墙';
Elapsed: 00:00:00.01
Execution Plan
----------------------------------------------------------
Plan hash value: 497066359
--------------------------------------------------------------------------------
------------------
| Id  | Operation                     | Name             | Rows  | Bytes | Cost
(%CPU)| Time     |
--------------------------------------------------------------------------------
------------------
|   0 | SELECT STATEMENT              |                  | &n