CODEWITHSUNDEEP
mysqlruby-on-railsactiverecord
randombits
randombits

Reputation: 48450

ActiveRecord configuration for reading from slave MySQL box

I have a very straight forward master/slave replication setup with MySQL. ActiveRecord is configured to hit the master hostname as would be expected in database.yml. My question is, is it currently possible to set an option for ActiveRecord to do all reads from a slave and leave writes to the master? I'm using Ruby on Rails/ActiveRecord 3.1.3. I haven't found any options to perform the following, just a single host entry field in database.yml. Is this currently possible?

Upvotes: 3

Views: 7010

Answers (3)

Yahya
Yahya

Reputation: 540

We also had the same requirement. Currently, this is not possible in ActiveRecord.

We spiked out 2 gems, Octopus and Makara. I have written a blog comparing these 2 gems : https://ypoonawala.wordpress.com/2015/11/15/octopus-vs-makara-read-write-adapters-for-activerecord-2/

In my opinion, Makara works well and makes up for the issues with Octopus.

Upvotes: 0

Daniel Cukier
Daniel Cukier

Reputation: 11942

There is the makara gem. It sends all SELECT statements to slaves and write operations to master.

Add this like to your Gemfile:

gem 'makara'

And then configure your database.ml like this:

production:
  adapter: 'mysql2_makara'
  database: 'MyAppProduction'
  # any other standard AR configurations

  # add a makara subconfig
  makara:

    # the following are default values
    blacklist_duration: 5
    master_ttl: 5
    sticky: true

    # list your connections with the override values (they're merged into the top-level config)
    # be sure to provide the role if master, role is assumed to be a slave if not provided
    connections:
      - role: master
        host: master.sql.host
      - role: slave
        host: slave1.sql.host
      - role: slave
        host: slave2.sql.host

Upvotes: 2

x1a4
x1a4

Reputation: 19485

Yes this is possible, but you need to use a gem for it; it's not built into Rails itself.

I use seamless database pool currently and it works great. Octopus is another alternative.

Upvotes: 4

Related Questions