var mysql = require('mysql');

var pool = mysql.createPool({

    host: 'localhost',

    user: 'nodejs',

    password: 'nodejs',

    database: 'nodejs',

    port: 3306

});

var selectSQL ="show variables like 'wait_timeout'";

pool.getConnection(function (err, conn) {

    if (err) console.log("POOL ==> " + err);

    function query(){

        conn.query(selectSQL, function (err, res) {

            console.log(new Date());

            console.log(res);

            conn.release();

        });

    }

    query();

    setInterval(query, 5000);

});