最近遇到一个测试项目，对SCAN_IP是否负载均衡有一个疑问？理论上说是可以负载均衡，自己做了一个测试验证一下。

事实证明，并不是轮训机制的负载均衡。


一个小小的脚本如下：


$less load_balance_scan.sh   

#!/bin/bash  

for i in {1..100}  

do  

echo $i

sqlplus -S system/oracle@orcl <

select instance_name from v\$instance;

select count(*) from t1;

EOF

sleep 1  

done  

exit 0 


$sh load_balance_scan.sh   

1


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


2


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


3


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


4


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


5


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


6


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


7


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


8


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


9


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


10


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


11


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


12


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


13


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


14


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


15


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


16


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


17


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


18


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


19


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


20


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


21


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


22


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


23


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


24


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


25


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


26


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


27


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


28


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


29


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


30


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


31


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


32


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


33


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


34


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


35


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


36


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


37


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


38


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


39


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


40


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


41


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


42


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


43


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


44


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


45


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


46


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


47


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


48


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


49


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


50


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


51


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


52


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


53


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


54


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


55


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


56


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


57


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


58


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


59


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


60


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


61


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


62


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


63


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


64


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


65


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


66


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


67


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


68


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


69


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


70


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


71


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


72


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


73


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


74


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


75


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


76


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


77


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


78


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


79


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


80


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


81


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


82


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


83


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


84


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


85


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


86


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


87


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


88


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


89


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


90


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


91


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


92


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


93


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


94


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


95


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


96


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


97


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


98


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


99


INSTANCE_NAME

----------------

orcl2



  COUNT(*)

----------

   2910624


100


INSTANCE_NAME

----------------

orcl1



  COUNT(*)

----------

   2910624


$