Citus Blog

The Citus 13.0 release is out and includes PostgreSQL 17.2 support! We know you’ve been waiting, and we’ve been hard at work adding features we believe will take your experience to the next level, focusing on bringing the Postgres 17 exciting improvements to you at distributed scale.

The Citus database is an open-source extension of Postgres that brings the power of Postgres to any scale, from a single node to a distributed database cluster. Since Citus is an extension, using Citus means you're also using Postgres, giving you direct access to the Postgres features. And the latest of such features came with Postgres 17 release! In addition, Citus 13 will be made available on the elastic clusters (preview) feature on Azure Database for PostgreSQL - Flexible Server, along with PostgreSQL 17 support, in the near future.

PostgreSQL 17 highlights include performance improvements in query execution for indexes, a revamped memory management system for vacuum, new monitoring and analysis features, expanded functionality for managing data in partitions, optimizer improvements, and enhancements for high-concurrency workloads. PostgreSQL 17 also expands on SQL syntax that benefits both new workloads and mission-critical systems, such as the addition of the SQL/JSON JSON_TABLE() command for developers, and the expansion of the MERGE command. For those of you who are interested in upgrading to Postgres 17 and scaling these new features of Postgres: you can upgrade to Citus 13.0!

Along with Postgres 17 support, Citus 13.0 also fixes important bugs, and we are happy to say that we had many community contributions here as well. These bugfixes focus on data integrity and correctness, crash and fault tolerance, and cluster management, all of which are critical for ensuring reliable operations and user confidence in a distributed PostgreSQL environment.

Let's take a closer look at what's new in Citus 13.0:

The new PostgreSQL 16 release is out, packed with exciting improvements and features—and Citus 12.1 brings them to you at scale, within just one week of the PG16 release.

As many of you likely know, Citus is an open source PostgreSQL extension that turns Postgres into a distributed database. Our team started integrating Citus with the PG16 beta and release candidates early-on, so that you could have a new Citus 12.1 release that is compatible with Postgres 16 as quickly as possible after PG16 came out.

There are a lot of good reasons to upgrade to Postgres 16—huge thanks to everyone who contributed into this Postgres release! PG16 highlights include query performance boost with more parallelism; load balancing with multiple hosts in libpq (contributed by my Citus teammate, Jelte Fennema-Nio); I/O monitoring with pg_stat_io; developer experience enhancements; finer-grained options for access control; logical replication from standby servers and other replication improvements, like using btree indexes in the absence of a primary key (contributed by one of my teammates, Onder Kalaci.)

The good news for those of you who care about distributed Postgres: Citus 12.1 is now available and adds support for Postgres 16.

In addition to Postgres 16 support, Citus 12.1 includes enhancements to schema-based sharding, which was recently added to Citus 12.0—and is super useful for multi-tenant SaaS applications.

Postgres community released a new feature, in Postgres 15.0, that performs actions to modify rows in the target table, using the data from a source. MERGE provides a single SQL statement that can conditionally INSERT, UPDATE or DELETE rows, a task that would otherwise require multiple procedural language statements, using INSERT with ON CONFLICT clause etc.

In this blog post, you will learn a high-level overview of the functioning of Postgres MERGE. It will delve into some of the practical use-cases, and subsequently elaborate on the different strategies employed by Citus for handling MERGE in a distributed environment.

What if you could automatically shard your PostgreSQL database across any number of servers and get industry-leading performance at scale without any special data modelling steps?

Our latest Citus open source release, Citus 12, adds a new and easy way to transparently scale your Postgres database: Schema-based sharding, where the database is transparently sharded by schema name.

Schema-based sharding gives an easy path for scaling out several important classes of applications that can divide their data across schemas:

• Multi-tenant SaaS applications
• Microservices that use the same database
• Vertical partitioning by groups of tables

Each of these scenarios can now be enabled on Citus using regular CREATE SCHEMA commands. That way, many existing applications and libraries (e.g. django-tenants) can scale out without any changes, and developing new applications can be much easier. Moreover, you keep all the other benefits of Citus, including distributed transactions, reference tables, rebalancing, and more.

Citus enables several different PostgreSQL use cases, but one of the most popular ones is to build scalable multi-tenant software as a service (SaaS) applications. The most common way to build a multi-tenant application on Citus is to distribute all your Postgres tables by a “tenant ID” column. That way rows are (hash-)distributed across nodes, while rows with the same tenant ID value are co-located on the same node for fast local joins, transactions, and foreign keys.

For those of you who build SaaS apps, one question many of you have is how active your tenants are. More specifically: What are your busiest tenants? How many queries is your application doing on behalf of your tenants, and how much CPU do those queries use?

The new 11.3 release to the open source Citus database extension gives you tenant monitoring—with instant visibility into your top tenants using the new citus_stat_tenants feature, which shows query counts and CPU usage over a configurable time period.

Our goal for the Citus extension is for you to be able to use all PostgreSQL features at any scale, with a seamless scaling experience. Distributed tables (or more generally “Citus tables”) are a powerful tool to get high performance at any scale. There are only a few remaining limitations when distributing a PostgreSQL table, but we are determined to solve them all. The Citus 11.2 release checks off another five SQL & DDL features that now work seamlessly on Citus tables. We also improved progress tracking for the shard rebalancer, so you know exactly what’s going on when rebalancing your cluster.

We also want PostgreSQL tools to work out-of-the-box even if you have a distributed PostgreSQL cluster. One of the most frequent questions we get on the Citus Slack from our open source users is how to set up high availability. Alexander Kukushkin, who is the primary maintainer of Patroni and recently joined the Citus database engine team, therefore developed a new version of Patroni which includes support for Citus!

Before we dive in, you can find detailed release notes for Citus 11.2 by the engineering team on our Updates page.

Citus is a distributed database that is built entirely as an open source PostgreSQL extension. In fact, you can install it in your PostgreSQL server without changing any PostgreSQL functionality. Citus simply gives PostgreSQL additional superpowers.

Being an extension also means we can keep adding new Postgres superpowers at a high pace. In the last release (11.0), we focused on giving you the ability to query from any node, opening up Citus for many new use cases, and we also made Citus fully open source. That means you can see everything we do on the Citus GitHub page (and star the repo if you’re a fan 😊). It also means that everyone can take advantage of shard rebalancing without write-downtime.

In the latest release (11.1), our Citus database team at Microsoft improved the application’s experience and avoided blocking writes during important operations like distributing tables and tenant isolation. These new capabilities built on the experience gained from developing the shard rebalancer, which uses logical replication to avoid blocking writes. In addition, we made the shard rebalancer faster and more user-friendly; also, we prepared for the upcoming PostgreSQL 15 release. This post gives you a quick tour of the major changes in Citus 11.1, including:

Citus 11.0 is here! Citus is a PostgreSQL extension that adds distributed database superpowers to PostgreSQL. With Citus, you can create tables that are transparently distributed or replicated across a cluster of PostgreSQL nodes. Citus 11.0 is a new major release, which means that it comes with some very exciting new features that enable new levels of scalability.

The biggest enhancement in Citus 11.0 is that you can now always run distributed queries from any node in the cluster because the schema & metadata are automatically synchronized. We already shared some of the details in the Citus 11.0 beta blog post, but we also have big surprise for those of you who use Citus open source that was not part of the initial beta.

When we do a new Citus release, we usually release 2 versions: The open source version and the enterprise release which includes a few extra features. However, there will be only one version of Citus 11.0, because everything in the Citus extension is now fully open source!

That means that you can now rebalance shards without blocking writes, manage roles across the cluster, isolate tenants to their own shards, and more. All this comes on top of the already massive enhancement in Citus 11.0: You can query your Citus cluster from any node, creating a truly distributed PostgreSQL experience.

Today we released Citus 11.0 beta, which is our first ever beta release of the Citus open source extension to Postgres. The reason we are releasing a beta version of 11.0 is that we are introducing a few fundamentally new capabilities, and we would like to get feedback from those of you who use Citus before we release Citus 11.0 to the world.

The biggest change in Citus 11.0 beta is that the schema and Citus metadata are now automatically synchronized throughout the database cluster. That means you can always query distributed tables from any node in a Citus cluster!

The easiest way to use Citus is to connect to the coordinator node and use it for both schema changes and distributed queries, but for very demanding applications, you now have the option to load balance distributed queries across the worker nodes in (parts of) your application by using a different connection string and factoring a few limitations.

Citus 10.2 is out! If you are not yet familiar with Citus, it is an open source extension to Postgres that transforms Postgres into a distributed database—so you can achieve high performance at any scale. The Citus open source packages are available for download. And Citus is also available in the cloud as a managed service, too.

You can see a bulleted list of all the changes in the CHANGELOG on GitHub. This post is your guide to what’s new in Citus 10.2, including some of these headline features.