mysqli::ping

mysqli_ping

(PHP 5, PHP 7, PHP 8)

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

Avviso

This function has been DEPRECATED as of PHP 8.4.0. Relying on this function is highly discouraged.

Descrizione

Stile orientato agli oggetti

public mysqli::ping(): bool

Stile procedurale

mysqli_ping(mysqli $mysql): bool

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.

Nota: 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.

Elenco dei parametri

link: Solo nello stile procedurale: un identificatore restituito da mysqli_connect() o mysqli_init()

Valori restituiti

Restituisce true in caso di successo, false in caso di fallimento.

Errori/Eccezioni

If mysqli error reporting is enabled (MYSQLI_REPORT_ERROR) and the requested operation fails, a warning is generated. If, in addition, the mode is set to MYSQLI_REPORT_STRICT, a mysqli_sql_exception is thrown instead.

Log delle modifiche

Versione	Descrizione
8.4.0	Both mysqli::ping() and mysqli_ping() are now deprecated. The `reconnect` feature has not been available as of PHP 8.2.0, making this function obsolete.

Esempi

Example #1 mysqli::ping() example

Stile orientato agli oggetti

<?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();
?>

Stile procedurale

<?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);
?>

I precedenti esempi visualizzeranno:

Our connection is ok!

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User Contributed Notes 3 notes

down

jay at grooveshark dot com ¶

10 years ago

This does not work with mysqlnd and is marked as wontfix: https://bugs.php.net/bug.php?id=52561

down

root at jusme dot org ¶

9 years 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.

down

snooops84 at googlemail dot com ¶

9 years 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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