Citus vs Riak: What are the differences?
Citus: Worry-free Postgres for SaaS. Built to scale out. Citus is worry-free Postgres for SaaS. Made to scale out, Citus is an extension to Postgres that distributes queries across any number of servers. Citus is available as open source, as on-prem software, and as a fully-managed service; Riak: A distributed, decentralized data storage system. Riak is a distributed database designed to deliver maximum data availability by distributing data across multiple servers. As long as your client can reach one Riak server, it should be able to write data. In most failure scenarios, the data you want to read should be available, although it may not be the most up-to-date version of that data.
Citus and Riak belong to "Databases" category of the tech stack.
"Multi-core Parallel Processing" is the primary reason why developers consider Citus over the competitors, whereas "High Performance " was stated as the key factor in picking Riak.
Citus and Riak are both open source tools. Citus with 3.64K GitHub stars and 273 forks on GitHub appears to be more popular than Riak with 3.24K GitHub stars and 530 GitHub forks.