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
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
|
--TEST--
MySQL PDO:query() vs. PDO::prepare() and MySQL error 2050
--SKIPIF--
<?php
require_once(dirname(__FILE__) . DIRECTORY_SEPARATOR . 'skipif.inc');
require_once(dirname(__FILE__) . DIRECTORY_SEPARATOR . 'mysql_pdo_test.inc');
MySQLPDOTest::skip();
$db = MySQLPDOTest::factory();
if (MYSQLPDOTest::isPDOMySQLnd())
die("skip libmysql only test");
?>
--FILE--
<?php
require_once(dirname(__FILE__) . DIRECTORY_SEPARATOR . 'mysql_pdo_test.inc');
$db = MySQLPDOTest::factory();
try {
printf("Native PS...\n");
$db->setAttribute(PDO::MYSQL_ATTR_DIRECT_QUERY, 0);
if (0 != $db->getAttribute(PDO::MYSQL_ATTR_DIRECT_QUERY))
printf("[004] Unable to turn off emulated prepared statements\n");
printf("Buffered...\n");
MySQLPDOTest::createTestTable($db);
$db->setAttribute(PDO::MYSQL_ATTR_USE_BUFFERED_QUERY, true);
$stmt = $db->query('SELECT id, label FROM test WHERE id = 1');
var_dump($stmt->fetchAll(PDO::FETCH_ASSOC));
$stmt = $db->query('SELECT id, label FROM test WHERE id = 1');
var_dump($stmt->fetchAll(PDO::FETCH_ASSOC));
printf("Unbuffered...\n");
MySQLPDOTest::createTestTable($db);
$db->setAttribute(PDO::MYSQL_ATTR_USE_BUFFERED_QUERY, false);
$stmt = $db->query('SELECT id, label FROM test WHERE id = 1');
var_dump($stmt->fetchAll(PDO::FETCH_ASSOC));
/*
NOTE - this will cause an error and it OK
When using unbuffered prepared statements MySQL expects you to
fetch all data from the row before sending new data to the server.
PDO::query() will prepare and execute a statement in one step.
After the execution of PDO::query(), MySQL expects you to fetch
the results from the line before sending new commands. However,
PHP/PDO will send a CLOSE message as part of the PDO::query() call.
The following happens:
$stmt = PDO::query(<some query>)
mysql_stmt_prepare()
mysql_stmt_execute()
$stmt->fetchAll()
mysql_stmt_fetch()
And now the right side of the expression will be executed first:
$stmt = PDO::query(<some query>)
PDO::query(<some query>)
mysql_stmt_prepare
mysql_stmt_execute
PHP continues at the left side of the expression:
$stmt = PDO::query(<some query>)
What happens is that $stmt gets overwritten. The reference counter of the
zval representing the current value of $stmt. PDO gets a callback that
it has to free the resources associated with the zval representing the
current value of stmt:
mysql_stmt_close
---> ERROR
---> execute() has been send on the line, you are supposed to fetch
---> you must not try to send a CLOSE after execute()
---> Error: 2050 (CR_FETCH_CANCELED)
---> Message: Row retrieval was canceled by mysql_stmt_close() call
---> MySQL does its best to recover the line and cancels the retrieval
PHP proceeds and assigns the new statement object/zval obtained from
PDO to $stmt.
Solutions:
- use mysqlnd
- use prepare() + execute() instead of query()
- as there is no explicit close() in PDO, try unset($stmt) before the new assignment
- fix PDO::query() [not the driver, fix PDO itself]
*/
$stmt = $db->query('SELECT id, label FROM test WHERE id = 1');
var_dump($stmt->fetchAll(PDO::FETCH_ASSOC));
$stmt = $db->prepare('SELECT id, label FROM test WHERE id = 1');
$stmt->execute();
var_dump($stmt->fetchAll(PDO::FETCH_ASSOC));
$stmt = $db->prepare('SELECT id, label FROM test WHERE id = 1');
$stmt->execute();
var_dump($stmt->fetchAll(PDO::FETCH_ASSOC));
unset($stmt);
$stmt = $db->query('SELECT id, label FROM test WHERE id = 1');
var_dump($stmt->fetchAll(PDO::FETCH_ASSOC));
unset($stmt);
$stmt = $db->query('SELECT id, label FROM test WHERE id = 1');
var_dump($stmt->fetchAll(PDO::FETCH_ASSOC));
} catch (PDOException $e) {
printf("[001] %s [%s] %s\n",
$e->getMessage(), $db->errorCode(), implode(' ', $db->errorInfo()));
}
print "done!";
?>
--CLEAN--
<?php
require dirname(__FILE__) . '/mysql_pdo_test.inc';
MySQLPDOTest::dropTestTable();
?>
--EXPECTF--
Native PS...
Buffered...
array(1) {
[0]=>
array(2) {
[%u|b%"id"]=>
%unicode|string%(1) "1"
[%u|b%"label"]=>
%unicode|string%(1) "a"
}
}
array(1) {
[0]=>
array(2) {
[%u|b%"id"]=>
%unicode|string%(1) "1"
[%u|b%"label"]=>
%unicode|string%(1) "a"
}
}
Unbuffered...
Warning: PDOStatement::fetchAll(): SQLSTATE[HY000]: General error: 2050 in %s on line %d
array(0) {
}
Warning: PDOStatement::fetchAll(): SQLSTATE[HY000]: General error: 2050 in %s on line %d
array(0) {
}
array(1) {
[0]=>
array(2) {
[%u|b%"id"]=>
%unicode|string%(1) "1"
[%u|b%"label"]=>
%unicode|string%(1) "a"
}
}
array(1) {
[0]=>
array(2) {
[%u|b%"id"]=>
%unicode|string%(1) "1"
[%u|b%"label"]=>
%unicode|string%(1) "a"
}
}
array(1) {
[0]=>
array(2) {
[%u|b%"id"]=>
%unicode|string%(1) "1"
[%u|b%"label"]=>
%unicode|string%(1) "a"
}
}
array(1) {
[0]=>
array(2) {
[%u|b%"id"]=>
%unicode|string%(1) "1"
[%u|b%"label"]=>
%unicode|string%(1) "a"
}
}
done!
|
