I am using node-mysql module (https://github.com/felixge/node-mysql) OR (http://utahjs.com/2010/09/22/nodejs-and-mysql-introduction/) .
Is this API handling connection pooling as well?
I mean with every user request I am calling Client.connect() to query the MySQL and to release the connection: Client.end().
Is this the right way, or should I connect/disconnect only once in a code.
I am learning from this document: https://github.com/felixge/node-mysql/blob/master/Readme.md
Update: Feb 2013 - pool support has been added to node-mysql, see docs
Example using built-in pool:
var pool = require('mysql').createPool(opts);
pool.getConnection(function(err, conn) {
conn.query('select 1+1', function(err, res) {
conn.release();
});
});
Pre 2013 solutions:
You can use node-pool or mysql-pool or use your own simple round-robin pool
function Pool(num_conns)
{
this.pool = [];
for(var i=0; i < num_conns; ++i)
this.pool.push(createConnection()); // your new Client + auth
this.last = 0;
}
Pool.prototype.get = function()
{
var cli = this.pool[this.last];
this.last++;
if (this.last == this.pool.length) // cyclic increment
this.last = 0;
return cli;
}
now you can hope to have all queries callbacks to execute in 1 second:
var p = new Pool(16);
for (var i=0; i < 10; ++i)
{
p.get().query('select sleep(1)', function() { console.log('ready'); } ); // server blocks for 1 second
}
I believe same node-mysql package provides connection pooling. Have a look
var express = require("express");
var mysql = require('mysql');
var app = express();
var pool = mysql.createPool({
connectionLimit : 100, //important
host : 'localhost',
user : 'root',
password : '',
database : 'address_book',
debug : false
});
function handle_database(req,res) {
pool.getConnection(function(err,connection){
if (err) {
connection.release();
res.json({"code" : 100, "status" : "Error in connection database"});
return;
}
console.log('connected as id ' + connection.threadId);
connection.query("select * from user",function(err,rows){
connection.release();
if(!err) {
res.json(rows);
}
});
connection.on('error', function(err) {
res.json({"code" : 100, "status" : "Error in connection database"});
return;
});
});
}
app.get("/",function(req,res){-
handle_database(req,res);
});
app.listen(3000);
Read complete case study (with and without pool) : http://codeforgeek.com/2015/01/nodejs-mysql-tutorial/
