1--TEST-- 2MySQL PDO:query() vs. PDO::prepare() and MySQL error 2050 3--SKIPIF-- 4<?php 5require_once(dirname(__FILE__) . DIRECTORY_SEPARATOR . 'skipif.inc'); 6require_once(dirname(__FILE__) . DIRECTORY_SEPARATOR . 'mysql_pdo_test.inc'); 7MySQLPDOTest::skip(); 8$db = MySQLPDOTest::factory(); 9if (MYSQLPDOTest::isPDOMySQLnd()) 10 die("skip libmysql only test"); 11?> 12--FILE-- 13<?php 14 require_once(dirname(__FILE__) . DIRECTORY_SEPARATOR . 'mysql_pdo_test.inc'); 15 $db = MySQLPDOTest::factory(); 16 17 try { 18 19 printf("Native PS...\n"); 20 $db->setAttribute(PDO::MYSQL_ATTR_DIRECT_QUERY, 0); 21 if (0 != $db->getAttribute(PDO::MYSQL_ATTR_DIRECT_QUERY)) 22 printf("[004] Unable to turn off emulated prepared statements\n"); 23 24 printf("Buffered...\n"); 25 MySQLPDOTest::createTestTable($db); 26 $db->setAttribute(PDO::MYSQL_ATTR_USE_BUFFERED_QUERY, true); 27 $stmt = $db->query('SELECT id, label FROM test WHERE id = 1'); 28 var_dump($stmt->fetchAll(PDO::FETCH_ASSOC)); 29 $stmt = $db->query('SELECT id, label FROM test WHERE id = 1'); 30 var_dump($stmt->fetchAll(PDO::FETCH_ASSOC)); 31 32 printf("Unbuffered...\n"); 33 MySQLPDOTest::createTestTable($db); 34 $db->setAttribute(PDO::MYSQL_ATTR_USE_BUFFERED_QUERY, false); 35 $stmt = $db->query('SELECT id, label FROM test WHERE id = 1'); 36 var_dump($stmt->fetchAll(PDO::FETCH_ASSOC)); 37 /* 38 NOTE - this will cause an error and it OK 39 When using unbuffered prepared statements MySQL expects you to 40 fetch all data from the row before sending new data to the server. 41 PDO::query() will prepare and execute a statement in one step. 42 After the execution of PDO::query(), MySQL expects you to fetch 43 the results from the line before sending new commands. However, 44 PHP/PDO will send a CLOSE message as part of the PDO::query() call. 45 46 The following happens: 47 48 $stmt = PDO::query(<some query>) 49 mysql_stmt_prepare() 50 mysql_stmt_execute() 51 52 $stmt->fetchAll() 53 mysql_stmt_fetch() 54 55 And now the right side of the expression will be executed first: 56 $stmt = PDO::query(<some query>) 57 PDO::query(<some query>) 58 mysql_stmt_prepare 59 mysql_stmt_execute 60 61 PHP continues at the left side of the expression: 62 63 $stmt = PDO::query(<some query>) 64 65 What happens is that $stmt gets overwritten. The reference counter of the 66 zval representing the current value of $stmt. PDO gets a callback that 67 it has to free the resources associated with the zval representing the 68 current value of stmt: 69 mysql_stmt_close 70 ---> ERROR 71 ---> execute() has been send on the line, you are supposed to fetch 72 ---> you must not try to send a CLOSE after execute() 73 ---> Error: 2050 (CR_FETCH_CANCELED) 74 ---> Message: Row retrieval was canceled by mysql_stmt_close() call 75 ---> MySQL does its best to recover the line and cancels the retrieval 76 77 PHP proceeds and assigns the new statement object/zval obtained from 78 PDO to $stmt. 79 80 Solutions: 81 - use mysqlnd 82 - use prepare() + execute() instead of query() 83 - as there is no explicit close() in PDO, try unset($stmt) before the new assignment 84 - fix PDO::query() [not the driver, fix PDO itself] 85 */ 86 87 $stmt = $db->query('SELECT id, label FROM test WHERE id = 1'); 88 var_dump($stmt->fetchAll(PDO::FETCH_ASSOC)); 89 90 $stmt = $db->prepare('SELECT id, label FROM test WHERE id = 1'); 91 $stmt->execute(); 92 var_dump($stmt->fetchAll(PDO::FETCH_ASSOC)); 93 94 $stmt = $db->prepare('SELECT id, label FROM test WHERE id = 1'); 95 $stmt->execute(); 96 var_dump($stmt->fetchAll(PDO::FETCH_ASSOC)); 97 98 unset($stmt); 99 $stmt = $db->query('SELECT id, label FROM test WHERE id = 1'); 100 var_dump($stmt->fetchAll(PDO::FETCH_ASSOC)); 101 102 unset($stmt); 103 $stmt = $db->query('SELECT id, label FROM test WHERE id = 1'); 104 var_dump($stmt->fetchAll(PDO::FETCH_ASSOC)); 105 106 } catch (PDOException $e) { 107 printf("[001] %s [%s] %s\n", 108 $e->getMessage(), $db->errorCode(), implode(' ', $db->errorInfo())); 109 } 110 111 print "done!"; 112?> 113--CLEAN-- 114<?php 115require dirname(__FILE__) . '/mysql_pdo_test.inc'; 116MySQLPDOTest::dropTestTable(); 117?> 118--EXPECTF-- 119Native PS... 120Buffered... 121array(1) { 122 [0]=> 123 array(2) { 124 [%u|b%"id"]=> 125 %unicode|string%(1) "1" 126 [%u|b%"label"]=> 127 %unicode|string%(1) "a" 128 } 129} 130array(1) { 131 [0]=> 132 array(2) { 133 [%u|b%"id"]=> 134 %unicode|string%(1) "1" 135 [%u|b%"label"]=> 136 %unicode|string%(1) "a" 137 } 138} 139Unbuffered... 140 141Warning: PDOStatement::fetchAll(): SQLSTATE[HY000]: General error: 2050 in %s on line %d 142array(0) { 143} 144 145Warning: PDOStatement::fetchAll(): SQLSTATE[HY000]: General error: 2050 in %s on line %d 146array(0) { 147} 148array(1) { 149 [0]=> 150 array(2) { 151 [%u|b%"id"]=> 152 %unicode|string%(1) "1" 153 [%u|b%"label"]=> 154 %unicode|string%(1) "a" 155 } 156} 157array(1) { 158 [0]=> 159 array(2) { 160 [%u|b%"id"]=> 161 %unicode|string%(1) "1" 162 [%u|b%"label"]=> 163 %unicode|string%(1) "a" 164 } 165} 166array(1) { 167 [0]=> 168 array(2) { 169 [%u|b%"id"]=> 170 %unicode|string%(1) "1" 171 [%u|b%"label"]=> 172 %unicode|string%(1) "a" 173 } 174} 175array(1) { 176 [0]=> 177 array(2) { 178 [%u|b%"id"]=> 179 %unicode|string%(1) "1" 180 [%u|b%"label"]=> 181 %unicode|string%(1) "a" 182 } 183} 184done!