1--TEST-- 2MySQL PDO:query() vs. PDO::prepare() and MySQL error 2050 3--EXTENSIONS-- 4pdo_mysql 5--SKIPIF-- 6<?php 7require_once(__DIR__ . DIRECTORY_SEPARATOR . 'mysql_pdo_test.inc'); 8MySQLPDOTest::skip(); 9$db = MySQLPDOTest::factory(); 10if (MYSQLPDOTest::isPDOMySQLnd()) 11 die("skip libmysql only test"); 12?> 13--FILE-- 14<?php 15 require_once(__DIR__ . DIRECTORY_SEPARATOR . 'mysql_pdo_test.inc'); 16 $db = MySQLPDOTest::factory(); 17 18 try { 19 20 printf("Native PS...\n"); 21 $db->setAttribute(PDO::MYSQL_ATTR_DIRECT_QUERY, 0); 22 if (0 != $db->getAttribute(PDO::MYSQL_ATTR_DIRECT_QUERY)) 23 printf("[004] Unable to turn off emulated prepared statements\n"); 24 25 printf("Buffered...\n"); 26 MySQLPDOTest::createTestTable($db); 27 $db->setAttribute(PDO::MYSQL_ATTR_USE_BUFFERED_QUERY, true); 28 $stmt = $db->query('SELECT id, label FROM test WHERE id = 1'); 29 var_dump($stmt->fetchAll(PDO::FETCH_ASSOC)); 30 $stmt = $db->query('SELECT id, label FROM test WHERE id = 1'); 31 var_dump($stmt->fetchAll(PDO::FETCH_ASSOC)); 32 33 printf("Unbuffered...\n"); 34 MySQLPDOTest::createTestTable($db); 35 $db->setAttribute(PDO::MYSQL_ATTR_USE_BUFFERED_QUERY, false); 36 $stmt = $db->query('SELECT id, label FROM test WHERE id = 1'); 37 var_dump($stmt->fetchAll(PDO::FETCH_ASSOC)); 38 /* 39 NOTE - this will cause an error and it OK 40 When using unbuffered prepared statements MySQL expects you to 41 fetch all data from the row before sending new data to the server. 42 PDO::query() will prepare and execute a statement in one step. 43 After the execution of PDO::query(), MySQL expects you to fetch 44 the results from the line before sending new commands. However, 45 PHP/PDO will send a CLOSE message as part of the PDO::query() call. 46 47 The following happens: 48 49 $stmt = PDO::query(<some query>) 50 mysql_stmt_prepare() 51 mysql_stmt_execute() 52 53 $stmt->fetchAll() 54 mysql_stmt_fetch() 55 56 And now the right side of the expression will be executed first: 57 $stmt = PDO::query(<some query>) 58 PDO::query(<some query>) 59 mysql_stmt_prepare 60 mysql_stmt_execute 61 62 PHP continues at the left side of the expression: 63 64 $stmt = PDO::query(<some query>) 65 66 What happens is that $stmt gets overwritten. The reference counter of the 67 zval representing the current value of $stmt. PDO gets a callback that 68 it has to free the resources associated with the zval representing the 69 current value of stmt: 70 mysql_stmt_close 71 ---> ERROR 72 ---> execute() has been send on the line, you are supposed to fetch 73 ---> you must not try to send a CLOSE after execute() 74 ---> Error: 2050 (CR_FETCH_CANCELED) 75 ---> Message: Row retrieval was canceled by mysql_stmt_close() call 76 ---> MySQL does its best to recover the line and cancels the retrieval 77 78 PHP proceeds and assigns the new statement object/zval obtained from 79 PDO to $stmt. 80 81 Solutions: 82 - use mysqlnd 83 - use prepare() + execute() instead of query() 84 - as there is no explicit close() in PDO, try unset($stmt) before the new assignment 85 - fix PDO::query() [not the driver, fix PDO itself] 86 */ 87 88 $stmt = $db->query('SELECT id, label FROM test WHERE id = 1'); 89 var_dump($stmt->fetchAll(PDO::FETCH_ASSOC)); 90 91 $stmt = $db->prepare('SELECT id, label FROM test WHERE id = 1'); 92 $stmt->execute(); 93 var_dump($stmt->fetchAll(PDO::FETCH_ASSOC)); 94 95 $stmt = $db->prepare('SELECT id, label FROM test WHERE id = 1'); 96 $stmt->execute(); 97 var_dump($stmt->fetchAll(PDO::FETCH_ASSOC)); 98 99 unset($stmt); 100 $stmt = $db->query('SELECT id, label FROM test WHERE id = 1'); 101 var_dump($stmt->fetchAll(PDO::FETCH_ASSOC)); 102 103 unset($stmt); 104 $stmt = $db->query('SELECT id, label FROM test WHERE id = 1'); 105 var_dump($stmt->fetchAll(PDO::FETCH_ASSOC)); 106 107 } catch (PDOException $e) { 108 printf("[001] %s [%s] %s\n", 109 $e->getMessage(), $db->errorCode(), implode(' ', $db->errorInfo())); 110 } 111 112 print "done!"; 113?> 114--CLEAN-- 115<?php 116require __DIR__ . '/mysql_pdo_test.inc'; 117MySQLPDOTest::dropTestTable(); 118?> 119--EXPECTF-- 120Native PS... 121Buffered... 122array(1) { 123 [0]=> 124 array(2) { 125 ["id"]=> 126 string(1) "1" 127 ["label"]=> 128 string(1) "a" 129 } 130} 131array(1) { 132 [0]=> 133 array(2) { 134 ["id"]=> 135 string(1) "1" 136 ["label"]=> 137 string(1) "a" 138 } 139} 140Unbuffered... 141 142Warning: PDOStatement::fetchAll(): SQLSTATE[HY000]: General error: 2050 Row retrieval was canceled by mysql_stmt_close() call in %s on line %d 143array(0) { 144} 145 146Warning: PDOStatement::fetchAll(): SQLSTATE[HY000]: General error: 2050 Row retrieval was canceled by mysql_stmt_close() call in %s on line %d 147array(0) { 148} 149array(1) { 150 [0]=> 151 array(2) { 152 ["id"]=> 153 string(1) "1" 154 ["label"]=> 155 string(1) "a" 156 } 157} 158array(1) { 159 [0]=> 160 array(2) { 161 ["id"]=> 162 string(1) "1" 163 ["label"]=> 164 string(1) "a" 165 } 166} 167array(1) { 168 [0]=> 169 array(2) { 170 ["id"]=> 171 string(1) "1" 172 ["label"]=> 173 string(1) "a" 174 } 175} 176array(1) { 177 [0]=> 178 array(2) { 179 ["id"]=> 180 string(1) "1" 181 ["label"]=> 182 string(1) "a" 183 } 184} 185done! 186