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Bug #38001 In PDO mysql running multiple queries with one exec, subsequent query fails
Submitted: 2006-07-04 09:12 UTC Modified: 2009-09-29 21:54 UTC
Votes:3
Avg. Score:5.0 ± 0.0
Reproduced:3 of 3 (100.0%)
Same Version:1 (33.3%)
Same OS:0 (0.0%)
From: mark-phpbugs at vectrex dot org dot uk Assigned:
Status: Closed Package: PDO related
PHP Version: 5.1.4 OS: Linux
Private report: No CVE-ID:
 [2006-07-04 09:12 UTC] mark-phpbugs at vectrex dot org dot uk
Description:
------------
When running multiple queries with one exec, the queries
succeed (or appear to succeed, with no exception), but a
subsequent query fails with 2013 Lost connection to MySQL server during query

I'm using MySQL 5.0.20a-Debian_2-log on Debian Linux. Client library version is 

"PDO Driver for MySQL, client library version => 5.0.22"

This is similar to "bogus" bug #37732 which affects mysqli - But in PDO there is no way to manually "consume" the empty result sets from an exec() - PDO should really do it automatically.

Reproduce code:
---------------
<?php

error_reporting(E_ALL);
	 
function DbInit()
{
	global $db;
	
	$options = array();
	
	$connstr = "mysql:host=localhost;dbname=test";
	$db = new PDO($connstr, "root", "", $options);
	$db->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION);
	
	// Make sure our connections use utf8.
	$db->exec("SET NAMES utf8");
}

function TestBatch()
{
	global $db;
	$sql = "CREATE TEMPORARY table b (t varchar(20))";
	$sql2 = " INSERT INTO b VALUES ('hello')";
	/* This works
	$db->exec($sql);
	$db->exec($sql2);
	*/
	/* This fails because the subsequent query gives 2013 Lost connection to MySQL server during query */
	$db->exec($sql . ";" . $sql2);	
	$sth = $db->query("SELECT * FROM b");
	var_dump($sth->fetchAll(PDO::FETCH_ASSOC));
}

DbInit();
TestBatch();

?>

Expected result:
----------------
array(1) {
  [0]=>
  array(1) {
    ["t"]=>
    string(5) "hello"
  }
}


Actual result:
--------------
Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[HY000]: General error: 2013 Lost connection to MySQL server during query' in /home/mark/progs/phptest/pdobatch.php:30
Stack trace:
#0 /home/mark/progs/phptest/pdobatch.php(30): PDO->query('SELECT * FROM b')
#1 /home/mark/progs/phptest/pdobatch.php(35): TestBatch()
#2 {main}
  thrown in /home/mark/progs/phptest/pdobatch.php on line 30


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 [2006-07-04 19:40 UTC] iliaa@php.net
Please try using this CVS snapshot:

  http://snaps.php.net/php5.2-latest.tar.gz
 
For Windows:
 
  http://snaps.php.net/win32/php5.2-win32-latest.zip

Works for me using MySQ 5.0.22
 [2006-07-04 22:11 UTC] mark-phpbugs at vetrex dot org dot uk
I've tried this with the latest snapshot, php5.2-200607042030, and the problem remains.
 [2006-07-12 01:00 UTC] php-bugs at lists dot php dot net
No feedback was provided for this bug for over a week, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".
 [2008-07-16 10:47 UTC] andrea at bhweb dot it
Although nasty, I found a workaround, like the one used in mysqli to 
consume the resultsets:

$stmt=$ppdb->prepare($query);
$stmt->execute();
do { $stmt->fetch(); $stmt->closeCursor(); ++$line; } while($stmt-
>nextRowset());

I found this only works using prepare and execute this way, not if you 
directly execute the query with query().

HTH
 [2008-07-16 22:16 UTC] uw@php.net
Multi-query is a MySQL specific feature and the PDO API does not support it properly. Multi-query are a potential security risk as they make SQL injections easier. This is against the idea of PDO to be secure. Check this article http://blog.ulf-wendel.de/?p=192 for details . 

PDO_MYSQLND will fix the bug:

nixnutz@ulflinux:~/php53> sapi/cli/php -r '$db = new PDO("mysql:host=localhost;dbname=test", "root", "root");  $db->exec("DROP TABLE IF EXISTS test; CREATE TABLE test(id INT); INSERT INTO test(id) VALUES(1)"); $stmt = $db->query("SELECT * FROM test"); var_dump($stmt->fetchAll(PDO::FETCH_ASSOC)); var_dump($db->errorInfo());'
array(1) {
  [0]=>
  array(1) {
    ["id"]=>
    string(1) "1"
  }
}
array(1) {
  [0]=>
  string(5) "00000"
}


 [2009-09-29 21:54 UTC] uw@php.net
Thank you for your bug report. This issue has already been fixed
in the latest released version of PHP, which you can download at 
http://www.php.net/downloads.php

Fixed in PHP 5.3+
 
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