PHP program mysql error mysql has gone away

This article mainly shares with you the memory-resident PHP program mysql error mysql has gone away. In the cli environment, the PHP program needs to run for a long time. The communication between the client and the MySQL server TCP connections are unstable.

The reasons for instability may be as follows:

• MySQL-Server will automatically cut off the connection within a certain period of time

• PHP When the program encounters an idle period and there is no MySQL query for a long time, MySQL-Server will also cut off the connection and recycle resources

• In other cases, execute the kill process in the MySQL server to kill a certain connection, and the MySQL server Restart

• Network jitter

At this time, the MySQL connection in the PHP program fails. If mysql_query is still executed, an error MySQL server has gone away will be reported. If the program cannot handle it, it directly encounters a fatal error and exits. Therefore, the PHP program needs to disconnect and reconnect.

Solution

mysql_ping

Many people have proposed the mysql_ping solution, which performs connection detection or timing every time mysql_query Connection detection.

This solution is not the best. The reason is: mysql_ping needs to actively detect the connection, which brings additional consumption. Executing mysql_ping regularly cannot solve the problem. For example, after just executing the mysql_ping test, the connection is closed;

Capture the error code and disconnect and reconnect

Its principle is: mysql_query detects the return value after execution. If mysql_query fails to return, the detection error code is found to be 2006/2013 (these 2 errors indicate connection Failure), execute mysql_connectAfter executing mysql_connect, re-execute mysql_queryIf mysql_query returns success, then the connection is valid Yes, this is a normal call.

Many well-known PHP resident process frameworks

• query method in swoole_framework.

$res = mysql_query($sql, $this->conn);if ($res === false)
{    if (mysql_errno($this->conn) == 2006 or mysql_errno($this->conn) == 2013)
    {        $r = $this->checkConnection();        if ($r === true)
        {
            continue;
        }
    }

• execute method of database connection class in workerman.

  protected function execute($query, $parameters = "")
    {        try {            ...
        } catch (PDOException $e) {
            // 服务端断开时重连一次            if ($e->errorInfo[1] == 2006 || $e->errorInfo[1] == 2013) {
                $this->closeConnection();
                $this->connect();            ...
        }
    }

Obviously, capturing the error code and disconnecting and reconnecting is a highly reliable and low-cost solution. It is recommended for everyone to use it in a permanent environment.

thinkphp + phpworkman A similar situation will occur when using

TP+workman. Starting from version V5.0.6+, TP supports Mysql’s disconnection and reconnection mechanism. It is turned off by default. If necessary, add

// 开启断线重连'break_reconnect' => true,

to the application/databases.php

database configuration file and it will be OK.

Related recommendations:

The memory-resident PHP program mysql reports an error

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