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
110
111
112
113
114
115
116
117
118
|
DROP TABLE IF EXISTS bug_53756 ;
CREATE TABLE bug_53756 (pk INT, c1 INT) ENGINE=InnoDB;
ALTER TABLE bug_53756 ADD PRIMARY KEY (pk);
INSERT INTO bug_53756 VALUES(1, 11), (2, 22), (3, 33), (4, 44);
# Select a less restrictive isolation level.
SET GLOBAL TRANSACTION ISOLATION LEVEL READ COMMITTED;
SET SESSION TRANSACTION ISOLATION LEVEL READ COMMITTED;
COMMIT;
# Start a transaction in the default connection for isolation.
START TRANSACTION;
SELECT @@transaction_isolation;
@@transaction_isolation
READ-COMMITTED
SELECT * FROM bug_53756;
pk c1
1 11
2 22
3 33
4 44
# connection con1 deletes row 1
START TRANSACTION;
SELECT @@transaction_isolation;
@@transaction_isolation
READ-COMMITTED
DELETE FROM bug_53756 WHERE pk=1;
# connection con2 deletes row 2
START TRANSACTION;
SELECT @@transaction_isolation;
@@transaction_isolation
READ-COMMITTED
DELETE FROM bug_53756 WHERE pk=2;
# connection con3 updates row 3
START TRANSACTION;
SELECT @@transaction_isolation;
@@transaction_isolation
READ-COMMITTED
UPDATE bug_53756 SET c1=77 WHERE pk=3;
# connection con4 updates row 4
START TRANSACTION;
SELECT @@transaction_isolation;
@@transaction_isolation
READ-COMMITTED
UPDATE bug_53756 SET c1=88 WHERE pk=4;
# connection con5 inserts row 5
START TRANSACTION;
SELECT @@transaction_isolation;
@@transaction_isolation
READ-COMMITTED
INSERT INTO bug_53756 VALUES(5, 55);
# connection con6 inserts row 6
START TRANSACTION;
SELECT @@transaction_isolation;
@@transaction_isolation
READ-COMMITTED
INSERT INTO bug_53756 VALUES(6, 66);
# connection con1 commits.
COMMIT;
# connection con3 commits.
COMMIT;
# connection con4 rolls back.
ROLLBACK;
# connection con6 rolls back.
ROLLBACK;
# The connections 2 and 5 stay open.
# connection default selects resulting data.
# Delete of row 1 was committed.
# Update of row 3 was committed.
# Due to isolation level read committed, these should be included.
# All other changes should not be included.
SELECT * FROM bug_53756;
pk c1
2 22
3 77
4 44
# connection default
#
# Crash server.
START TRANSACTION;
INSERT INTO bug_53756 VALUES (666,666);
SET SESSION debug="+d,crash_commit_before";
COMMIT;
ERROR HY000: Lost connection to MySQL server during query
#
# disconnect con1, con2, con3, con4, con5, con6.
#
# Restart server.
#
# Select recovered data.
# Delete of row 1 was committed.
# Update of row 3 was committed.
# These should be included.
# All other changes should not be included.
# Delete of row 2 and insert of row 5 should be rolled back
SELECT * FROM bug_53756;
pk c1
2 22
3 77
4 44
# Clean up.
DROP TABLE bug_53756;
|
