Lukas Fittl

If you’ve worked with Ruby on Rails you likely have some understanding of how your database works with Rails, traditionally that has always meant specifying a single database per environment in your config/database.yml, possibly together with an environment setting like DATABASE_URL. Based on that configuration all reads and writes will access the database.

With Rails 6 this is about to change, thanks to the work of Eileen M. Uchitelle together with contributors from GitHub, Basecamp and Shopify. In the upcoming Rails 6 (currently in RC1), you will be able to easily change which database server you are connecting to, to support a variety of scenarios such as using read replicas and splitting your database into dedicated components.

The most interesting part, which we wanted to detail in this post, is related to configuring automatic queries against a read replicas, or follower database.

We rolled out a new database migration feature for the Citus fully-managed database as a service—the Warp migration feature—as part of our Citus Cloud 2 announcement. Today I wanted to walk through Citus Cloud’s warp migration feature in more detail. Before we drill in, we should probably take a step back and look at what typically (and sometimes painfully) goes on for a large database migration.

This week at RailsConf, we found ourselves sharing a lot of tips for using PostgreSQL with Rails. We thought it might be worthwhile to write up many of these and share more broadly. Here you’ll find some tips that will help you in debugging and improving performance of your database from your Rails app.

And now, on to the code.

Today we’re happy to announce our new activerecord-multi-tenant Ruby library, which enables easy scale-out of applications that are built on top of Ruby on Rails and follow a multi-tenant data model.

This Ruby library has evolved from our experience working with customers, scaling out their multi-tenant apps, and patching some restrictions that ActiveRecord and Rails currently have when it comes to automatic query building. It is based on the excellent acts_as_tenant library, and extends it for the particular use-case of a distributed multi-tenant database like Citus.