pt-online-schema-change migrations

Runs regular Rails/ActiveRecord migrations via the Percona Toolkit pt-online-schema-change tool.

Installation

Add this line to your application's Gemfile:

gem 'pt-osc'

And then execute:

$ bundle

Or install it yourself as:

$ gem install pt-osc

Usage

Set your database adapter to be pt_osc in your application's database.yml. Specify pt-online-schema-change flags in a percona hash in the config. e.g.

environment:
  host: localhost
  username: root
  database: rails
  percona:
    defaults-file: /etc/mysql/percona-user.cnf
    recursion-method: "'dsn=D=percona,t=slaves'"

Additional options for the percona hash include:

• run_mode: Specify 'execute' to actually run pt-online-schema-change when the migration runs. Specify 'print' to output the commands to run to STDOUT instead. Default is 'print'.

Caveats

This gem is not considered production ready. There will be bugs. It is tested against:

• ActiveRecord 3.2 branch
  • Ruby 1.9.2
  • Ruby 2.0.0
  • Ruby 2.1.2

Support for other versions of Ruby or ActiveRecord is unknown and not guaranteed.