Citus vs Druid: What are the differences?
Developers describe Citus as "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. On the other hand, Druid is detailed as "Fast column-oriented distributed data store". Druid is a distributed, column-oriented, real-time analytics data store that is commonly used to power exploratory dashboards in multi-tenant environments. Druid excels as a data warehousing solution for fast aggregate queries on petabyte sized data sets. Druid supports a variety of flexible filters, exact calculations, approximate algorithms, and other useful calculations.
Citus and Druid are primarily classified as "Databases" and "Big Data" tools respectively.
"Multi-core Parallel Processing" is the primary reason why developers consider Citus over the competitors, whereas "Real Time Aggregations" was stated as the key factor in picking Druid.
Citus and Druid are both open source tools. It seems that Druid with 8.22K GitHub stars and 2.05K forks on GitHub has more adoption than Citus with 3.5K GitHub stars and 263 GitHub forks.