为什么针对node.js的Mysql Native驱动程序的查询执行时间如此之长？ 还有其他选择吗？

Question

Why does same query take around 300 ms more than actual execution time when using Mysql native driver for Nodejs , even with or without using "create pool" options?

Please refer highlighted section in below attached screenshot

Also for native driver execution time, please see below attached screenshot:

Codebase for node.js Mysql Native driver

db.js

var mysql = require('mysql');
var connectionpool = mysql.createPool({
    connectionLimit: 100, //important
    host: 'localhost',
    user: config.development.username,
    password: config.development.password,
    database: config.development.database,
    multipleStatements: true,
});

    exports.getConnection = function(callback) {
        connectionpool.getConnection(callback);
    };

emp.js

var connections = require('../config/db');
     var pre_query = new Date().getTime();
        var sqlstatements = "select  * from employees where recordstate<>'raw'and  DATE(createdAt) " + "between ('1982-03-24') and ('2017-04-23')    order by employeesID desc limit 20 offset 0;" + "select COUNT(*) as count   from employees where recordstate<>'raw'and  " + "DATE(createdAt) between ('1982-03-24') and ('2017-04-23')    order by employeesID desc";
        connections.getConnection(function(err, c) {
            console.log(sqlstatements)
            c.query(sqlstatements, function(err, projects) {


                console.log(err);
                if (!err) {
                    c.release();

                    var red = new Object();
                    red.rows = JSON.parse(JSON.stringify(projects[0]));
                    red.count = JSON.parse(JSON.stringify(projects[1]))[0].count;
                    var post_query = new Date().getTime();
                    // calculate the duration in seconds
                    var duration = (post_query - pre_query) / 1000;
                    console.log(duration)
                        // console.log(red);
                    res.json(red);

                }
            })
        })

Answer 1

Your measurement in JS includes connection setup and all the processing of the results. The times reported in MySQL Workbench (and the MySQL terminal client) are only what the server reports (running a query and result transmission). Alone the connection setup probably takes most of the 300ms. Try moving the pre_query init to the line right before running the actual query. And end the time measurement directly after that (before the console.log(err) call. This delivers a result comparable to that reported by other client tools.