Citus Blog

What happens to your database when your SaaS application is an overnight success? When your customer base has grown bigger than you’d always hoped but it all happened so fast and now what do you do? What happens when your SaaS application needs to scale, but your database is getting more and more sluggish?

Until recently, the conventional wisdom for SaaS startups is that you should launch your application on top of an open source relational database, like Postgres or MySQL. And that once you become an overnight success, you will need to slog your way through a period of fail whales while you re-architect your app to go to NoSQL. Or while you re-architect your app to shard at the application layer. Ick.

There are a number of data architectures you could use when building a multi-tenant app. Some, such as using one database per customer or one schema per customer, have trade-offs when it comes to larger scale. The other option is to build the notion of tenancy directly into the logic of your SaaS application. With django-multitenant and Citus, built-in tenancy becomes much easier to put in place for your application without having to re-invent the wheel yourself.

Our django-multitenant Python library, enables easy scale out of applications that are built on top of Django and follow a multi tenant data model. This Python library has evolved from our experience working with SaaS customers, scaling out their multi-tenant apps.

We recently presented a webcast on when and what to consider when scaling your multi-tenant application. In case you missed it, the recording and slides are below. Within the webcast session, we cover:

If you’re building a SaaS application, you probably already have the notion of tenancy built in your data model. Typically, most information relates to tenants / customers / accounts and your database tables capture this natural relation.

With smaller amounts of data (10s of GB), it’s easy to throw more hardware at the problem and scale up your database. As these tables grow however, you need to think about ways to scale your multi-tenant database across dozens or hundreds of machines.

After our blog post on sharding a multi-tenant app with Postgres, we received a number of questions on architectural patterns for multi-tenant databases and when to use which. At a high level, developers have three options:

Whether you’re building marketing analytics, a portal for e-commerce sites, or an application to cater to schools, if you’re building an application and your customer is another business then a multi-tenant approach is the norm. The same code runs for all customers, but each customer sees their own private data set, except in some cases of holistic internal reporting.

Early in your application’s life customer data has a simple structure which evolves organically. Typically all information relates to a central customer/user/tenant table. With a smaller amount of data (10’s of GB) it’s easy to scale the application by throwing more hardware at it, but what happens when you’ve had enough success and data that you have no longer fits in memory on a single box, or you need more concurrency? You scale out, often painfully.