Mojo::MySQL5 - Pure-Perl non-blocking I/O MySQL Connector


  use Mojo::MySQL5;

  # Create a table
  my $mysql = Mojo::MySQL5->new('mysql://username@/test');
    'create table names (id integer auto_increment primary key, name text)');

  # Insert a few rows
  my $db = $mysql->db;
  $db->query('insert into names (name) values (?)', 'Sara');
  $db->query('insert into names (name) values (?)', 'Stefan');

  # Insert more rows in a transaction
    my $tx = $db->begin;
    $db->query('insert into names (name) values (?)', 'Baerbel');
    $db->query('insert into names (name) values (?)', 'Wolfgang');

  # Insert another row and return the generated id
  say $db->query('insert into names (name) values (?)', 'Daniel')

  # Select one row at a time
  my $results = $db->query('select * from names');
  while (my $next = $results->hash) {
    say $next->{name};

  # Select all rows blocking
  $db->query('select * from names')
    ->hashes->map(sub { $_->{name} })->join("\n")->say;

  # Select all rows non-blocking
    sub {
      my $delay = shift;
      $db->query('select * from names' => $delay->begin);
    sub {
      my ($delay, $err, $results) = @_;
      $results->hashes->map(sub { $_->{name} })->join("\n")->say;

  # Send and receive notifications non-blocking
  $mysql->pubsub->listen(foo => sub {
    my ($pubsub, $payload) = @_;
    say "foo: $payload";
    $pubsub->notify(bar => $payload);
  $mysql->pubsub->listen(bar => sub {
    my ($pubsub, $payload) = @_;
    say "bar: $payload";
  $mysql->pubsub->notify(foo => 'MySQL rocks!');

  Mojo::IOLoop->start unless Mojo::IOLoop->is_running;


Mojo::MySQL5 makes MySQL a lot of fun to use with the Mojolicious real-time web framework.

Database handles are cached automatically, so they can be reused transparently to increase performance. And you can handle connection timeouts gracefully by holding on to them only for short amounts of time.

  use Mojolicious::Lite;
  use Mojo::MySQL5;

  helper mysql =>
    sub { state $mysql = Mojo::MySQL5->new('mysql://sri:s3cret@localhost/db') };

  get '/' => sub {
    my $c  = shift;
    my $db = $c->mysql->db;
    $c->render(json => $db->query('select now() as time')->hash);


Every database connection can only handle one active query at a time, this includes asynchronous ones. So if you start more than one, they will be put on a waiting list and performed sequentially. To perform multiple queries concurrently, you have to use multiple connections.

  # Performed sequentially (10 seconds)
  my $db = $mysql->db;
  $db->query('select sleep(5)' => sub {...});
  $db->query('select sleep(5)' => sub {...});
  # Performed concurrently (5 seconds)
  $mysql->db->query('select sleep(5)' => sub {...});
  $mysql->db->query('select sleep(5)' => sub {...});

All cached database handles will be reset automatically if a new process has been forked, this allows multiple processes to share the same Mojo::MySQL5 object safely.

Note that this whole distribution is EXPERIMENTAL and will change without warning!


Mojo::MySQL5 inherits all events from Mojo::EventEmitter and can emit the following new ones.


  $mysql->on(connection => sub {
    my ($mysql, $db) = @_;

Emitted when a new database connection has been established.


Mojo::MySQL5 implements the following attributes.


  my $max = $mysql->max_connections;
  $mysql  = $mysql->max_connections(3);

Maximum number of idle database handles to cache for future use, defaults to 5.


  my $migrations = $mysql->migrations;
  $mysql         = $mysql->migrations(Mojo::MySQL5::Migrations->new);

Mojo::MySQL5::Migrations object you can use to change your database schema more easily.

  # Load migrations from file and migrate to latest version

MySQL does not support nested transactions and DDL transactions. DDL statements cause implicit COMMIT. ROLLBACK will be called if any step of migration script fails, but only DML statements after the last implicit or explicit COMMIT can be reverted. Not all MySQL storage engines (like MYISAM) support transactions.

This means database will most likely be left in unknown state if migration script fails. Use this feature with caution and remember to always backup your database.


  my $pubsub = $mysql->pubsub;
  $mysql     = $mysql->pubsub(Mojo::MySQL5::PubSub->new);

Mojo::MySQL5::PubSub object you can use to send and receive notifications very efficiently, by sharing a single database connection with many consumers.

  # Subscribe to a channel
  $mysql->pubsub->listen(news => sub {
    my ($pubsub, $payload) = @_;
    say "Received: $payload";

  # Notify a channel
  $mysql->pubsub->notify(news => 'MySQL rocks!');


  my $url = $mysql->url;
  $url  = $mysql->url(

Connection URL.


Use url->options.

See Mojo::MySQL5::Connection for list of supported options.


Use url->password.


Use url->username.


Mojo::MySQL5 inherits all methods from Mojo::EventEmitter and implements the following new ones.


  my $db = $mysql->db;

Get Mojo::MySQL5::Database object for a cached or newly created database handle. The database handle will be automatically cached again when that object is destroyed, so you can handle connection timeouts gracefully by holding on to it only for short amounts of time.

  # Add up all the money
  say $mysql->db->query('select * from accounts')
    ->hashes->reduce(sub { $a->{money} + $b->{money} });


  $mysql = $mysql->from_string('mysql://user@/test');

Parse configuration from connection string.

  # Just a database

  # Username and database

  # Username, password, host and database

  # Username, domain socket and database

  # Username, database and additional options


  my $mysql = Mojo::MySQL5->new;
  my $mysql = Mojo::MySQL5->new('mysql://user:s3cret@host:port/database');
  my $mysql = Mojo::MySQL5->new(
    url => Mojo::MySQL5::URL->new(
      host => 'localhost',
      port => 3306,
      username => 'user',
      password => 's3cret',
      options => { utf8 => 1, found_rows => 1 }

Construct a new Mojo::MySQL5 object and parse connection string with "from_string" if necessary.


This is the class hierarchy of the Mojo::MySQL5 distribution.


Jan Henning Thorsen,

Svetoslav Naydenov,

A lot of code in this module is taken from Sebastian Riedel's Mojo::Pg.


Copyright (C) 2015, Svetoslav Naydenov.

This program is free software, you can redistribute it and/or modify it under the terms of the Artistic License version 2.0.


Mojo::Pg Async Connector for PostgreSQL using DBD::Pg,,

Mojo::mysql Async Connector for MySQL using DBD::mysql,,