A small node.js program using the mysql package to show huge amount of memory consumption on large volumes of high frequency queries.

mysql-memory-leaker.js

var Mysql = require('mysql')
var fs = require('fs')

var MysqlOptions = {
    //connectionLimit: 30,
    host: 'localhost',
    user: 'root',
    password: 'mysqlroot123',
    database: 'LeakyDB'
}

var logStream = fs.createWriteStream('console-file.log', {flags: 'w+', defaultEncoding: 'utf8', mode: 0o666, autoClose: true, fd: null});
var logMemStream = fs.createWriteStream('memory.log', {flags: 'w+', defaultEncoding: 'utf8', mode: 0o666, autoClose: true, fd: null});

function logln(str) {
  logStream.write("[" + new Date().toString() + "] " + str + "\n");
}

function logMem(str) {
  logMemStream.write("[" + new Date().toString() + "] " + str + "\n");
}

var leakTester = {
  MysqlDB: Mysql.createConnection(MysqlOptions),

  makeBadSqlQuery: function makeBadSqlQuery(scripCode, lastTradedPrice) {
    var badCode = scripCode + ' 123'
    var queryStatement = "UPDATE LeakyDB.live_market SET current_market_price=" + lastTradedPrice + " WHERE scrip_code=" + badCode;
    var self = this;
    this.MysqlDB.query(queryStatement, function mysqlDBQueryReturn(err, results, fields) {
      if (err) {
        logln("Query failed. Code : " + badCode + ' with error : ' + JSON.stringify(err));
      } else {
        logln('Query succeed. results = ' + JSON.stringify(results));
      }
      err = null;
      results = null;
      fields = null;
    });
    queryStatement = null;
  },

  syncToMysql: function syncToMysql() {
    var heapUsed = process.memoryUsage().heapUsed;
    logMem("Program is using " + heapUsed + " bytes of Heap.");
    try {
      for(i = 0; i < 10000; i++) {
        try {
          this.makeBadSqlQuery(i, i);
        } catch(ex) {
          logln('Error while updating scrip with code : ' + i + ' with error : ' + ex.message);
        }
      }
    } catch(ex) {
      logln('Exception while syncing : ' + ex.message);
    }
  }
};

setInterval(function taskDoer() {
  logln("Triggering sync");
  leakTester.syncToMysql();
}, 2000);

logln("Process started");