单个SCAN_IP是否负载均衡？

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：

<rac01:orcl1:/u01/app/oracle/product/12.1.0/dbhome_1/network/admin>$less load_balance_scan.sh   

#!/bin/bash  

for i in {1..100}  

do  

echo $i

sqlplus -S system/oracle@orcl <<EOF

select instance_name from v\$instance;

select count(*) from t1;

EOF

sleep 1  

done  

exit 0 

<rac01:orcl1:/u01/app/oracle/product/12.1.0/dbhome_1/network/admin>$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

<rac01:orcl1:/u01/app/oracle/product/12.1.0/dbhome_1/network/admin>$

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