<?php


$host = 'localhost';
$db   = 'enter_your_db';
$user = 'enter_your_username';
$pass = 'enter_your_password';
$charset = 'utf8mb4';


$dsn = "mysql:host=$host;dbname=$db;charset=$charset";
$opt = [
    PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION,
    PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
    PDO::ATTR_EMULATE_PREPARES   => false,
    PDO::ATTR_PERSISTENT => false
];
$pdo = new PDO($dsn, $user, $pass, $opt);

echo "pid=(".getmypid().")n";

$stmt = $pdo->query('SELECT connection_id() as connid');
$row = $stmt->fetch();

echo "mysql connection id =(".$row['connid'].")n";


$stmt = $pdo->query('SELECT GET_LOCK("foobar", 2)');
$row = $stmt->fetch();


var_dump($row);
echo "nn";
sleep(10);

pid=(18378)
mysql connection id =(71)
array(1) {
  ["GET_LOCK("foobar", 2)"]=>
  int(1)
}

pid=(18393)
mysql connection id =(73)
array(1) {
  ["GET_LOCK("foobar", 2)"]=>
  int(0)
}

GET_LOCK

GET_LOCK