php, mysql server has gone away

Question

What is wrong, when you connect to the DB on the LINE BEFORE THE QUERY, and you still get "MySQL server has gone away"?

check this example code:

mysql_connect("localhost", "xxx", "xxx") or die(mysql_error());
mysql_select_db("xxx") or die(mysql_error());
$sql = mysql_query("SELECT id FROM db");
while ($data = mysql_fetch_assoc($sql)) {
$ids[] = $data[id];
}

foreach ($ids as $id) {
$content = file_get_contents("http://www.id.com/?id=$id");
if (stristr($content, "the id is ok man")) {
mysql_connect("localhost", "xxx", "xxx") or die(mysql_error());
mysql_select_db("xxx") or die(mysql_error());
mysql_query("UPDATE db SET status = 'OK' WHERE id = '$id'");
}
}

mysql server is gone away, i get that in the foreach loop. BTW i need to connect in the foreachloop, because it may take along time before it finds something to update (like 1-2 minutes), and then for sure i will get mysql server has gone away.

Answer 1

I assume your issue is that the script may execute for a very long time before sending the first UPDATE query.

You should check the wait_timeout value in my.cnf. You can check your wait_timeout by running the query "SHOW VARIABLES;"

You can also try to piece of code to do a reconnect:

if (!mysql_ping ($conn)) {
   //here is the major trick, you have to close the connection (even though its not currently working) for it to recreate properly.
   mysql_close($conn);
   $conn = mysql_connect('localhost','user','pass');
   mysql_select_db('db',$conn);
}

Combining with your code it would be:

mysql_connect("localhost", "xxx", "xxx") or die(mysql_error());
mysql_select_db("xxx") or die(mysql_error());
$sql = mysql_query("SELECT id FROM db");
while ($data = mysql_fetch_assoc($sql)) {
    if (!mysql_ping ()) {
       //here is the major trick, you have to close the connection (even though its not currently working) for it to recreate properly.
       mysql_close();
       mysql_connect("localhost", "xxx", "xxx") or die(mysql_error());
       mysql_select_db("xxx") or die(mysql_error());
    }

    $ids[] = $data['id'];
    $content = file_get_contents("http://www.id.com/?id=$id");
    if (stristr($content, "the id is ok man")) {
        mysql_query("UPDATE db SET status = 'OK' WHERE id = '$id'");
    }
}

Answer 2

We got that error this week at work here is the official documentation from MySQL : http://dev.mysql.com/doc/refman/5.0/en/gone-away.html

This section also covers the related Lost connection to server during query error.

The most common reason for the MySQL server has gone away error is that the server timed out and closed the connection.