node mysql .on('packet', function(packet) error

Question

I need to make a query every X amount of time. I am running node version 0.8.12 and the latest node mysql When running the following code

  function testmysql()
{
    mysqlCon.connect();
    mysqlCon.query('SELECT 1 + 1 AS solution', function(err, rows, fields) {
    if (err) throw err;

    console.log('The solution is: ', rows[0].solution);
});

mysqlCon.end();
}

    var period = 2000;
    var interval  = setInterval(function(){

    testmysql();
}, period);

I get the following error.

\nodetest\node_modules\mysql\lib\protocol\Protocol.js:95
    .on('packet', function(packet) {
     ^
TypeError: Cannot call method 'on' of undefined
    at Protocol._enqueue (\nodetest\node_modules\mysql\lib\protocol\Protocol.j
s:95:6)
    at Protocol.handshake (\nodetest\node_modules\mysql\lib\protocol\Protocol.
js:37:41)
    at Connection.connect (\nodetest\node_modules\mysql\lib\Connection.js:37:1
8)
    at testmysql (\nodetest\index.js:1112:10)
    at Timer.<anonymous> (\nodetest\index.js:1143:1)
    at Timer.exports.setInterval.timer.ontimeout (timers.js:234:14)

Though when testmysql() is not in another function it runs correctly.

What am I doing incorrectly? or rather how would I perform this loop query? Thanks

Answer 1

Try this instead - it's better design and it should hopefully resolve your error:

function testmysql(mysqlConnection)
{
    mysqlConnection.query('SELECT 1 + 1 AS solution', function(err, rows, fields) {
        if (err) throw err;

        console.log('The solution is: ', rows[0].solution);
    });
}

var period = 2000;
var interval  = setInterval(function(){
    var mysqlCon = mysql.createConnection({host:'localhost',user:'testadmin',password:'pass',database:'mydb'});        
    mysqlCon.connect();
    testmysql(mysqlCon);
    mysqlCon.end();
}, period);

Answer 2

ok... I deconstructed the project line by line... and the code that was causing it was this -

 var EventEmitter = require('events').EventEmitter
 , on = EventEmitter.prototype.on;
 EventEmitter.prototype.on = function () {
this._maxListeners = Infinity;
on.apply(this, arguments);
};

I was using this snippet because node_redis was throwing an error or warning of a memory leak due to the max listeners limit every time someone would join as I am using redisstore with socket.io. I Removed the code and I am no longer getting the memory leak errors perhaps because I took the latest node_redis version.

So sorry for the trouble and thanks for the help.