Heroic vs RethinkDB: What are the differences?

Heroic: A scalable time series database based on Cassandra and Elasticsearch, by Spotify. Heroic is Spotify's in-house time series database. It was built to address the challenges Spotify was facing with near real-time data collection and presentation at scale; RethinkDB: JSON. Scales to multiple machines with very little effort. Open source. RethinkDB is built to store JSON documents, and scale to multiple machines with very little effort. It has a pleasant query language that supports really useful queries like table joins and group by, and is easy to setup and learn.

Heroic and RethinkDB belong to "Databases" category of the tech stack.

Some of the features offered by Heroic are:

• heroic-core contains the com.spotify.heroic.HeroicCore class which is the central building block for setting up a Heroic instance.
• heroic-elasticsearch-utils is a collection of utilities for interacting with Elasticsearch. This is separate since we have more than one backend that needs to talk with elasticsearch.
• heroic-parser provides an Antlr4 implementation of com.spotify.heroic.grammar.QueryParser, which is used to parse the Heroic DSL.

On the other hand, RethinkDB provides the following key features:

• JSON data model and immediate consistency.
• Distributed joins, subqueries, aggregation, atomic updates.
• Secondary, compound, and arbitrarily computed indexes.

Heroic and RethinkDB are both open source tools. It seems that RethinkDB with 22.4K GitHub stars and 1.74K forks on GitHub has more adoption than Heroic with 710 GitHub stars and 89 GitHub forks.