Citus 10 is out! New features include columnar storage & Citus on a single node—plus we’ve open-sourced the shard rebalancer. Read the Citus 10 blog.

Skip navigation

Citus Blog

Articles tagged: citus tips

Citus is an extension to Postgres that lets you distribute your application’s workload across multiple nodes. Whether you are using Citus open source or using Citus as part of a managed Postgres service in the cloud, one of the first things you do when you start using Citus is to distribute your tables. While distributing your Postgres tables you need to decide on some properties such as distribution column, shard count, colocation. And even before you decide on your distribution column (sometimes called a distribution key, or a sharding key), when you create a Postgres table, your table is created with an access method.

Previously you had to decide on these table properties up front, and then you went with your decision. Or if you really wanted to change your decision, you needed to start over. The good news is that in Citus 10, we introduced 2 new user-defined functions (UDFs) to make it easier for you to make changes to your distributed Postgres tables.

Keep reading

One of the big new things in Citus 10 is that you can now shard Postgres on a single Citus node. So in addition to using the Citus extension to Postgres to scale out Postgres across a distributed cluster, you can now also:

  • Try out Citus on a single node with just a few simple commands
  • Shard Postgres on a single Citus node to be “scale-out-ready”
  • Simplify CI/CD pipelines by testing with single-node Citus

The Citus 10 release is chock full of new capabilities like columnar storage for Postgres, the open sourcing of the shard rebalancer, as well as the feature we are going to explore here: using Citus on a single node. No matter what type of application you run on top of Citus—multi-tenant SaaS apps, customer-facing analytics dashboards, time-series workloads, high-throughput transactional apps—there is something for everyone in Citus 10.

Keep reading

One of the main reasons people use the Citus extension for Postgres is to distribute the data in Postgres tables across multiple nodes. Citus does this by splitting the original Postgres table into multiple smaller tables and putting these smaller tables on different nodes. The process of splitting bigger tables into smaller ones is called sharding—and these smaller Postgres tables are called “shards”. Citus then allows you to query the shards as if they were still a single Postgres table.

One of the big changes in Citus 10—in addition to adding columnar storage, and the new ability to shard Postgres on a single Citus node—is that we open sourced the shard rebalancer.

Yes, that’s right, we have open sourced the shard rebalancer! The Citus 10 shard rebalancer gives you an easy way to rebalance shards across your cluster and helps you avoid data hotspots over time. Let’s dig into the what and the how.

Keep reading
Jeff Davis

Citus 10 brings columnar compression to Postgres

Written byBy Jeff Davis | March 6, 2021Mar 6, 2021

Citus 10 is out! Check out the Citus 10 blog post for all the details. Citus is an open source extension to Postgres (not a fork) that enables scale-out, but offers other great features, too. See the Citus docs and the Citus github repo and README.

This post will highlight Citus Columnar, one of the big new features in Citus 10. You can also take a look at the columnar documentation. Citus Columnar can be used with or without the scale-out features of Citus.

Postgres typically stores data using the heap access method, which is row-based storage. Row-based tables are good for transactional workloads, but can cause excessive IO for some analytic queries.

Columnar storage is a new way to store data in a Postgres table. Columnar groups data together by column instead of by row; and compresses the data, too. Arranging data by column tends to compress well, and it also means that queries can skip over columns they don’t need. Columnar dramatically reduces the IO needed to answer a typical analytic query—often by 10X!

Keep reading

Once you start using the Citus extension to distribute your Postgres database, you may never want to go back. But what if you just want to experiment with Citus and want to have the comfort of knowing you can go back? Well, as of Citus 9.5, now there is a new undistribute_table() function to make it easy for you to, well, to revert a distributed table back to being a regular Postgres table.

If you are familiar with Citus, you know that Citus is an open source extension to Postgres that distributes your data (and queries) to multiple machines in a cluster—thereby parallelizing your workload and scaling your Postgres database horizontally. When you start using Citus—whether you’re using Citus open source or whether you’re using Citus as part of a managed service in the cloud—usually the first thing you need to do is distribute your Postgres tables across the cluster.

Keep reading

Page 1 of 1