Skip to content


Subversion checkout URL

You can clone with
Download ZIP
(!! The project is dead !!) node-mysql-pool is MySQL connection pool for node.js on top of Felix Geisendörfer's MySQL client node-mysql.
tree: 7354961e02

Fetching latest commit…

Cannot retrieve the latest commit at this time

Failed to load latest commit information.



node-mysql-pool is MySQL connection pool for node.js on top of Felix Geisendörfer's great MySQL client node-mysql.

Using a connection pool instead of a single connection should render a remarkable speed-up, when you have many short living connections, e.g. with message board applications.

Current status

This module is currently not backed by proper unit testing. Nevertheless I found it stable for my testings.

If you find an error, please file an issue!



This module was only tested using node >= 0.4.x. It may work for older versions, but I am not going to actively support them.

The node-mysql-pool works even with unknown forks of node-mysql, as long as

  • the last parameter of a method is callback function
  • you connect using connect(), disconnection using end(),
  • the constructor gets an object containing the parameters,
  • no events are emitted when supplying a callback function, and
  • the when the first parameter of a callback is set, it denotes an error.

Otherwise the requirements are the same as for node-mysql.


var MySQLPool = require("./node-mysql-pool").MySQLPool,
    client = new MySQLPool({database: "test"}); = 'root'; = 'root';


client.query("SELECT 'Hello, World!' AS hello", function(err, rows, fields) {
  if(err) throw err;

for(var i = 0; i < 10; ++i) {
  client.query("SELECT SLEEP(2), ? AS i", [i], function(err, rows, fields) {
    if(err) throw err;
    console.log("Slept: " + rows[0].i);


The API of this module is as similar to node-mysql as possible, with three exceptions:

  • You must always supply a callback function. Using listeners is not supported.
  • You connect using connectPool([poolsize], [cb]) and shut the pool down using endPool([cb]).
  • Property x, when not supplied while creation, are to be set to

new mysqlPool.Pool([options])

Creates a new, currently empty, pool. Any property for the signle connections or the connectionpool, resp., can be set using the options object.

client.poolSize = 1

The number of connections to establish to the server.

client.Client = require("mysql").Client

If you do not want the npm version of node-mysql -- e.g. because you forked and tweaked it for you purposes -- you can supply a different Client object. = undefined

Property xyz of the Client object.

See the original documentation of node-mysql for more property related information.

client.connectPool([poolsize], [cb])

Establishes a new connection pool with the size of poolsize.

If the parameter poolsize is omitted, the value of client.poolsize, or 1 is used.

cb = function(err, result={ [connections: Number], [errors: Array] })

Only if all connection attemps failed err is supplied. If some connections failed, result.error will contain a list of Errors. If some or all connections succeeded, results.connections will contains the pool's size.


Shuts down all connections, not waiting for any enqueued and waiting queries. Active queries won't be aborted, though.

cb will be called back once for every shut down connection. (Subject to change!)

client.xzy(..., cb)

All methods of the Client object will be supported.

See the original documentation of node-mysql for information.


  • Twink twice before calling useDatabase(...): It will only affect a single random connection. Do you really want that?
  • Invoking destroy kills a random connection. While it won't couse harm right away, you may observe errors while shutting down.

event: 'error' (err)

Emitted if end only if an error occurred and no callback function was supplied. You should always supply a callback function!


  • The endPool([cb]) method has a strange API.


node-mysql-pool is licensed under the MIT license.

Something went wrong with that request. Please try again.