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https://github.com/thiagopradi/octopus_sharding_example

Sample Rails app using Octopus Library to Enable database Sharding on ActiveRecord
https://github.com/thiagopradi/octopus_sharding_example

Last synced: 29 days ago
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Sample Rails app using Octopus Library to Enable database Sharding on ActiveRecord

Host: GitHub
URL: https://github.com/thiagopradi/octopus_sharding_example
Owner: thiagopradi
Created: 2010-06-14T04:35:41.000Z (over 14 years ago)
Default Branch: master
Last Pushed: 2011-07-03T17:01:11.000Z (over 13 years ago)
Last Synced: 2024-11-29T12:08:14.313Z (about 1 month ago)
Language: Ruby
Homepage: http://github.com/tchandy/octopus
Size: 579 KB
Stars: 12
Watchers: 4
Forks: 7
Open Issues: 4
Metadata Files:
- Readme: README.mkdn

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README

Octopus Sharding Example

This is a sample rails application using sharding with Octopus. This application have the User information on master database, and all informations after login are stored in the shard, based on `country` attribute of the current_user. Available shards are: brazil, mexico and canada.

How-to

Octopus is simple to use, just follow the steps:

- Add the gem to your Gemfile:

gem 'ar-octopus', '0.0.12', :require => "octopus"

- Create a shards.yml file inside config directory, that looks like this:


development:

  shards:

    canada:

      host: localhost

      adapter: mysql

      database: canada_shard

    brazil:

      host: localhost

      adapter: mysql

      database: brazil_shard

    mexico:

      host: localhost

      adapter: mysql

      database: mexico_shard

After this, you need to select what shard to use. This could be done with around_filter in controller, or setting the shard manually. This code in application_controller.rb that selects the shard:


class ApplicationController < ActionController::Base

  around_filter :select_shard

  def select_shard()

    if user_signed_in?

      using(current_user.country.to_sym) { yield }

    else

      yield     

    end

  end

end

If the user isn't logged in, the shard will be the master. after this, it will pick the country attribute, passes to Octopus, and all queries will be sent to the selected shard. If you want to specify manually what shard to use, this is the syntax:

 User.using(:brazil).all

Important!

Each ActiveRecord object knows where is the source shard. if you want to move objects between shards, you need to specify what shard to sent, like this:

 

# This will save the user in the brazil shard

@user = User.using(:brazil).first

@user.name = "New Name"

@user.save()

# This will move the data to another shard:

new_user = User.new

new_user.attributes = @user.attributes

new_user.save()

More info could be found at Octopus Wiki

Thanks

This project is sponsored by the Ruby Summer of Code,
and my mentors Mike Perham and Amit Agarwal.