1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
|
call mtr.add_suppression("192.0.2.4");
flush status;
TRUNCATE TABLE performance_schema.host_cache;
flush user_resources;
flush privileges;
select @@global.debug;
@@global.debug
select @@global.max_connect_errors;
@@global.max_connect_errors
100
select @@global.max_user_connections;
@@global.max_user_connections
0
select @@global.max_connections;
@@global.max_connections
151
select `User`, `Host` from mysql.`user` where `host` like '%\\%%';
User Host
select `User`, `Host` from mysql.`user` where `user` like '192.%';
User Host
select `User`, `Host` from mysql.`user` where `user` like '2001:%';
User Host
select `User`, `Host` from mysql.`user` where `user` like 'santa.claus.%';
User Host
CREATE USER 'user4'@'santa.claus.ipv4.example.com';
GRANT SELECT ON test.* TO 'user4'@'santa.claus.ipv4.example.com';
SET global debug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_fake_ipv4,getaddrinfo_fake_good_ipv4";
SELECT "Con4 is alive" AS "";
Con4 is alive
SELECT current_user() AS "";
user4@santa.claus.ipv4.example.com
SET global debug= default;
====================================================================
Testing index for columns IP
====================================================================
############ Explain for Query ####################################
explain select SUM_CONNECT_ERRORS
from performance_schema.host_cache
where IP = "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL # NULL no matching row in const table
############ Explain for Query ####################################
explain select SUM_CONNECT_ERRORS
from performance_schema.host_cache
where IP > "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE host_cache NULL ALL PRIMARY NULL NULL NULL # 33.33 Using where
############ Explain for Query ####################################
explain select SUM_CONNECT_ERRORS
from performance_schema.host_cache
where IP < "2";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE host_cache NULL ALL PRIMARY NULL NULL NULL # 33.33 Using where
############ Explain for Query ####################################
explain select SUM_CONNECT_ERRORS
from performance_schema.host_cache
where IP = "192.0.2.4";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE host_cache NULL const PRIMARY PRIMARY 258 const # 100.00 NULL
############# Explain End #########################################
flush status;
select SUM_CONNECT_ERRORS
from performance_schema.host_cache
where IP = "192.0.2.4";
SUM_CONNECT_ERRORS
#
OK: handler_read_key incremented
====================================================================
Testing index for columns HOST
====================================================================
############ Explain for Query ####################################
explain select SUM_CONNECT_ERRORS
from performance_schema.host_cache
where HOST = "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE host_cache NULL ref HOST HOST 258 const # 100.00 NULL
############ Explain for Query ####################################
explain select SUM_CONNECT_ERRORS
from performance_schema.host_cache
where HOST > "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE host_cache NULL ALL HOST NULL NULL NULL # 33.33 Using where
############ Explain for Query ####################################
explain select SUM_CONNECT_ERRORS
from performance_schema.host_cache
where HOST < "2";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE host_cache NULL ALL HOST NULL NULL NULL # 33.33 Using where
############ Explain for Query ####################################
explain select SUM_CONNECT_ERRORS
from performance_schema.host_cache
where HOST = "santa.claus.ipv4.example.com";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE host_cache NULL ref HOST HOST 258 const # 100.00 NULL
############# Explain End #########################################
flush status;
select SUM_CONNECT_ERRORS
from performance_schema.host_cache
where HOST = "santa.claus.ipv4.example.com";
SUM_CONNECT_ERRORS
#
OK: handler_read_key incremented
REVOKE SELECT ON test.* FROM 'user4'@'santa.claus.ipv4.example.com';
DROP USER 'user4'@'santa.claus.ipv4.example.com';
|
