Skip to content
(!! The project is dead !!) node-mysql-pool is MySQL connection pool for node.js on top of Felix Geisendörfer's MySQL client node-mysql.
Find file
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 two exceptions:

  • You must always supply a callback function. Using listeners is not supported.
  • Property x, when not supplied while creation, are to be set to

When called back, this will be the used connection.

new mysqlPool.Pool([options])

Creates a new, currently empty, pool. Any property for the single 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.connect([poolsize], [cb])

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

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.

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 once for every shut down connection. (Subject to change!)

client.useDatabase(database, cb)

Changes the database for every connection.


Kills every connection. You do not want do use this method!

client.xzy(..., cb)

All methods of the Client object will be supported -- with connect(...), end(...), useDatabase(...) and destroy(...) being overwritten.

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


  • You must supply a callback method, if you have any parameters.
  • No events are emitted but error.

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 end([cb]), destroy([cb]) and useDatabase(db, cb) methods have a strange API.


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

Something went wrong with that request. Please try again.