PHP 5.6.29 Released

mysqli::ping

mysqli_ping

(PHP 5, PHP 7)

mysqli::ping -- mysqli_pingPings a server connection, or tries to reconnect if the connection has gone down

Description

Object oriented style

bool mysqli::ping ( void )

Procedural style

bool mysqli_ping ( mysqli $link )

Checks whether the connection to the server is working. If it has gone down and global option mysqli.reconnect is enabled, an automatic reconnection is attempted.

Note: The php.ini setting mysqli.reconnect is ignored by the mysqlnd driver, so automatic reconnection is never attempted.

This function can be used by clients that remain idle for a long while, to check whether the server has closed the connection and reconnect if necessary.

Parameters

link

Procedural style only: A link identifier returned by mysqli_connect() or mysqli_init()

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example #1 mysqli::ping() example

Object oriented style

<?php
$mysqli 
= new mysqli("localhost""my_user""my_password""world");

/* check connection */
if ($mysqli->connect_errno) {
    
printf("Connect failed: %s\n"$mysqli->connect_error);
    exit();
}

/* check if server is alive */
if ($mysqli->ping()) {
    
printf ("Our connection is ok!\n");
} else {
    
printf ("Error: %s\n"$mysqli->error);
}

/* close connection */
$mysqli->close();
?>

Procedural style

<?php
$link 
mysqli_connect("localhost""my_user""my_password""world");

/* check connection */
if (mysqli_connect_errno()) {
    
printf("Connect failed: %s\n"mysqli_connect_error());
    exit();
}

/* check if server is alive */
if (mysqli_ping($link)) {
    
printf ("Our connection is ok!\n");
} else {
    
printf ("Error: %s\n"mysqli_error($link));
}

/* close connection */
mysqli_close($link);
?>

The above examples will output:

Our connection is ok!
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User Contributed Notes 3 notes

up
7
jay at grooveshark dot com
2 years ago
This does not work with mysqlnd and is marked as wontfix: https://bugs.php.net/bug.php?id=52561
up
2
root at jusme dot org
1 year ago
As jay at grooveshark dot com very helpfully pointed out, the mysqlnd driver which is becoming pretty standard does not obey reconnect commands. If you have a DB wrapper class (which hopefully you do) you can implement your own version of ping() such as:

<?php

class db extends mysqli
{
    private
$db_host;
    private
$db_user;
    private
$db_pass;
    private
$db_name;
    private
$persistent;

    public function
__construct($db_host, $db_user, $db_pass, $db_name, $persistent = true)
    {
       
$this->db_host = $db_host;
       
$this->db_user = $db_user;
       
$this->db_pass = $db_pass;
       
$this->db_name = $db_name;
       
$this->persistent = $persistent;

       
parent::init();
       
parent::options(MYSQLI_OPT_CONNECT_TIMEOUT, 1);
        @
parent::real_connect(($this->persistent ? 'p:' : '') . $this->db_host, $this->db_user, $this->db_pass, $this->db_name);

        if (
$this->connect_errno)
            die(
"All DB servers down!\n");
    }

    public function
ping()
    {
        @
parent::query('SELECT LAST_INSERT_ID()');

        if (
$this->errno == 2006)
           
$this->__construct($this->db_host, $this->db_user, $this->db_pass, $this->db_name, $this->persistent);
    }
...
}

$db = new db(DB_HOST, DB_USER, DB_PASS, DB_NAME);
// Some code that potentially takes a really long time to execute goes here
// Ping for safety to try to gracefully reconnect
$db->ping();
// Now we should be able to run queries again
$db->query('SELECT LAST_INSERT_ID()');

?>

If you wanted you could even put "$this->ping();" at the top of db::query() to avoid any explicit reconnection calls but I wouldn't recommend it due to the (slight) overhead of running the cheap "SELECT LAST_INSERT_ID()" query every time prior to running your real intended query. There are probably even cheaper queries to run in favor of "SELECT LAST_INSERT_ID()" but it was the first that came to mind and is cheap enough for most purposes since you shouldn't be calling ping() a whole bunch anyway.
up
0
snooops84 at googlemail dot com
1 year ago
The behaviour about the option mysqli.reconnect is default set to Off at Debian PHP Packages. So i would recommend to update the first line description about the recommendation at the option mysqli.reconnect. (practice note ;))
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