Pdo: MySQL Server Has Gone Away

PDO: MySQL server has gone away

The B.5.2.9. MySQL server has gone away section of the MySQL manual has a list of possible causes for this error.

Maybe you are in one of those situations ? -- Especially considering you are running a long operation, the point about wait_timeout might be interesting...

PDO: MySQL server has gone away, can't catch exception

As determined in the comments, you're running this code within another namespace. This means that catch (PDOException $e) is actually catch (\Your\Namespace\PDOException $e) so will not work. You'll either need to prefix the class with a leading backslash to put it in the global namespace:

catch(\PDOException $e){
    $this->error = $e->getMessage();
    return $this->error;
}

Or use the class at the beginning of your code.

use \PDOException;

PDO general error: 2006 mysql server has gone away

$db->exec('SET session wait_timeout=60');

MySQL server has gone away, PDO and max_allowed_packet in PHP

Thanks for your respective answers. After few days of investigations, I decided to reset PDO MySQL connection every 250 seconds. I know it is not the best in class solution but it is at least a solution to avoid the problem.

PHP error shows MySQL server has gone away error

The most common reason for the MySQL server has gone away error is
that the server timed out and closed the connection. In this case, you
normally get one of the following error codes (which one you get is
operating system-dependent).

What error code you are getting?

CR_SERVER_GONE_ERROR The client couldn't send a question to the
server. CR_SERVER_LOST The client didn't get an error when writing to
the server, but it didn't get a full answer (or any answer) to the
question.

By default, the server closes the connection after eight hours if nothing has happened. You can change the time limit by setting the wait_timeout variable when you start mysqld. See Section 5.1.8, “Server System Variables”.

If you have a script, you just have to issue the query again for the client to do an automatic reconnection. This assumes that you have automatic reconnection in the client enabled (which is the default for the mysql command-line client).

Some other common reasons for the MySQL server has gone away error are:

You (or the db administrator) has killed the running thread with a
KILL statement or a mysqladmin kill command.

You tried to run a query after closing the connection to the server.
This indicates a logic error in the application that should be
corrected.

A client application running on a different host does not have the
necessary privileges to connect to the MySQL server from that host.

You got a timeout from the TCP/IP connection on the client side. This
may happen if you have been using the commands: mysql_options(...,
MYSQL_OPT_READ_TIMEOUT,...) or mysql_options(...,
MYSQL_OPT_WRITE_TIMEOUT,...). In this case increasing the timeout may
help solve the problem.

You have encountered a timeout on the server side and the automatic
reconnection in the client is disabled (the reconnect flag in the
MYSQL structure is equal to 0).

You are using a Windows client and the server had dropped the
connection (probably because wait_timeout expired) before the command
was issued.

The problem on Windows is that in some cases MySQL does not get an
error from the OS when writing to the TCP/IP connection to the server,
but instead gets the error when trying to read the answer from the
connection.

The solution to this is to either do a mysql_ping() on the connection
if there has been a long time since the last query (this is what
Connector/ODBC does) or set wait_timeout on the mysqld server so high
that it in practice never times out.

You can also get these errors if you send a query to the server that
is incorrect or too large. If mysqld receives a packet that is too
large or out of order, it assumes that something has gone wrong with
the client and closes the connection. If you need big queries (for
example, if you are working with big BLOB columns), you can increase
the query limit by setting the server's max_allowed_packet variable,
which has a default value of 64MB. You may also need to increase the
maximum packet size on the client end. More information on setting the
packet size is given in Section B.6.2.9, “Packet Too Large”.

An INSERT or REPLACE statement that inserts a great many rows can also
cause these sorts of errors. Either one of these statements sends a
single request to the server irrespective of the number of rows to be
inserted; thus, you can often avoid the error by reducing the number
of rows sent per INSERT or REPLACE.

It is also possible to see this error if host name lookups fail (for
example, if the DNS server on which your server or network relies goes
down). This is because MySQL is dependent on the host system for name
resolution, but has no way of knowing whether it is working—from
MySQL's point of view the problem is indistinguishable from any other
network timeout.

You may also see the MySQL server has gone away error if MySQL is
started with the --skip-networking option.

Another networking issue that can cause this error occurs if the MySQL
port (default 3306) is blocked by your firewall, thus preventing any
connections at all to the MySQL server.

You can also encounter this error with applications that fork child
processes, all of which try to use the same connection to the MySQL
server. This can be avoided by using a separate connection for each
child process.

You have encountered a bug where the server died while executing the
query.

You can check whether the MySQL server died and restarted by executing mysqladmin version and examining the server's uptime. If the client connection was broken because mysqld crashed and restarted, you should concentrate on finding the reason for the crash. Start by checking whether issuing the query again kills the server again. See Section B.6.3.3, “What to Do If MySQL Keeps Crashing”.

MySQL server has gone away using PDO connection in PHP

I had to upgrade MySQL to version 5.7.10 and now everything is working correctly.

mysql server has gone away in PDO

In my case, PDO was taking single connection and if the loop size is big, connection was getting timed out. So, I increased the timeout of PDO connection for all cli's.

$this->connection = new PDO($this->dsn, $this->username, $this->password);
//Increase the session time out for all cli's
if(php_sapi_name() == 'cli'){
      $query = $this->connection->prepare("set session wait_timeout=10000,interactive_timeout=10000,net_read_timeout=10000");
      $query->execute();
}

Issue is resolved now.

---

Related Topics