From: rgagnon24 at gmail dot com
Operating system: CentOS 5.9
PHP version: 5.3.23
Package: MySQL related
Bug Type: Bug
Bug description:mysqlnd persistent connection handling out of control
Description:
------------
When PHP 5.3 is compiled with
--enable-mysqlnd=shared
--with-mysql=shared,mysqlnd
--with-mysqli=shared,mysqlnd
--with-pdo-mysql=shared,mysqlnd
In order to use the native driver, persistent connections using PDO don't
appear to use any kind of managable or determinate connection pooling.
Running the test script below via apache web server, refreshing the page
every few seconds (10 or 12 times), will produce at least 10 connections to
the database as shown by the mysql "SHOW PROCESSLIST" command... yet the
phpinfo() section will indicate a number that is not the same as the actual
number of connections.
In my test prior to posting, I had 10 actual connections (of which 9 were
sleeping, and the 10th one was just used to run the test query) and
phpinfo() showed 5 active_persistent_connections, and pconnect_success was
8 (under the mysqlnd stats section).
This leads me to believe there may be a memory leak in the area of code
where the module is managing the connection pool. If no memory leak, the
management of the connections is off somehow as idle connections to a
production webserver are ridiculously high.
Test script:
---------------
<?php
$options = array(
PDO::ATTR_PERSISTENT => true,
PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
PDO::MYSQL_ATTR_USE_BUFFERED_QUERY => true,
);
$host_name = 'database_host';
$database_name = 'some_database';
$port = 3306;
$username = 'db_user';
$password = 'db_pass';
$dsn = sprintf("mysql:host=%s;dbname=%s;port=%d",
$host_name, $database_name, $port);
$dbh = new PDO($dsn, $username, $password, $options);
$sql = 'SELECT * FROM test WHERE id=1 LIMIT 1';
print "<pre>";
$stmt = $dbh->query($sql, PDO::FETCH_ASSOC);
while ($row = $stmt->fetch()) {
var_dump($row);
}
$stmt->closeCursor();
print '</pre>';
Expected result:
----------------
active_persistent_connections and pconnect_success should be accurate to
match what you are really doing. Also the command line 'netstat -anp|grep
:3306|grep httpd|grep ESTABLISHED" should show a limit at some point on the
number of connections that are persistent, or they should get re-used.
Actual result:
--------------
There are a lot of unaccounted for idle ESTABLISHED in the netstat command,
for connections from httpd to mysql when mysqlnd indicates there are not
that many.
--
Edit bug report at https://bugs.php.net/bug.php?id=64549&edit=1
--
Try a snapshot (PHP 5.4):
https://bugs.php.net/fix.php?id=64549&r=trysnapshot54
Try a snapshot (PHP 5.3):
https://bugs.php.net/fix.php?id=64549&r=trysnapshot53
Try a snapshot (trunk):
https://bugs.php.net/fix.php?id=64549&r=trysnapshottrunk
Fixed in SVN: https://bugs.php.net/fix.php?id=64549&r=fixed
Fixed in release: https://bugs.php.net/fix.php?id=64549&r=alreadyfixed
Need backtrace: https://bugs.php.net/fix.php?id=64549&r=needtrace
Need Reproduce Script: https://bugs.php.net/fix.php?id=64549&r=needscript
Try newer version: https://bugs.php.net/fix.php?id=64549&r=oldversion
Not developer issue: https://bugs.php.net/fix.php?id=64549&r=support
Expected behavior: https://bugs.php.net/fix.php?id=64549&r=notwrong
Not enough info:
https://bugs.php.net/fix.php?id=64549&r=notenoughinfo
Submitted twice:
https://bugs.php.net/fix.php?id=64549&r=submittedtwice
register_globals: https://bugs.php.net/fix.php?id=64549&r=globals
PHP 4 support discontinued: https://bugs.php.net/fix.php?id=64549&r=php4
Daylight Savings: https://bugs.php.net/fix.php?id=64549&r=dst
IIS Stability: https://bugs.php.net/fix.php?id=64549&r=isapi
Install GNU Sed: https://bugs.php.net/fix.php?id=64549&r=gnused
Floating point limitations: https://bugs.php.net/fix.php?id=64549&r=float
No Zend Extensions: https://bugs.php.net/fix.php?id=64549&r=nozend
MySQL Configuration Error: https://bugs.php.net/fix.php?id=64549&r=mysqlcfg
