IBM DB2

vs

QuestDB

RethinkDB is a scalable, open-source database designed for real-time applications. When your app polls your database for data, it becomes slow, unscalable, and cumbersome to maintain. RethinkDB solves this by providing a new database access model, where developers can instruct the database to continuously push updated query results to their applications, without polling.

BigchainDB allows developers and enterprise to deploy blockchain proof-of-concepts, platforms and applications with a blockchain database, supporting a wide range of industries and use cases. BigchainDB provides high throughput, low latency, powerful query functionality, decentralized control, immutable data storage and built-in asset support, BigchainDB is like a database with blockchain characteristics.

NuoDB is a distributed relational database management system utilizing SQL. The database is architected to meet the rapidly evolving demands of today's enterprises, NuoDB can be used to deploy on-premise, extend to the cloud, scale on demand, eliminate downtime and reduce total cost of ownership. All while maintaining SQL compatibility and a workflow that most developers are familiar with.

TimescaleDB is a leading open-source relational database for time-series data. The database is provided as fully managed or self‑hosted software, giving the power of choice back to developers and organizations. Timescale gives you all the reliability and flexibility of PostgreSQL. It allows you to use regular SQL to construct queries to better understand your products and your users. While achieve 10-100x faster queries than PostgreSQL, InfluxDB, and MongoDB with native optimizations for time-series.

A Chinese developed open-source NewSQL database that supports analytical processing and hybrid transactional workloads. TiDB is licensed under the Apache 2.0 license and primarily developed by PingCAP, Inc. The database provides high availability with strong consistency and horizontal scaling and is compatible with MySQL.

OpenTSDB is a free and open-source distributed, scalable Time Series Database written on top of Apache HBase. OpenTSDB was designed to address a common need: store, index and serve metrics collected from computer systems such as network gear, operating systems and applications, at a large scale, and make this data easily accessible and graphable. OpenTSDB allows you to collect thousands of metrics from tens of thousands of hosts and applications, at a high rate and will never delete or downsample data and can easily store hundreds of billions of data points.