QuestDB

vs

TiDB

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.

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.

DuckDB is an embeddable SQL OLAP database management system. It provides developers with serious data management features such as extensive support for complex SQL queries and a large function library, with windwed functions. DuckDB is also ACID compliant and proivides transactional guarantees through custom, bulk-optimized MVCC. DuckDB is released fully open source under the permissive MIT Licens. The entire source code of DuckDB is freely available on GitHub

MongoDB is an open-source document-oriented distributed database built for modern applications. MongoDB uses JSON-like documents with optional schemas and is classified as a NoSQL database. The database is freely distributed under the Server Side Public License, but MongoDB provides commercial version of the database for enterprise-scale applications.

ArangoDB is a database system that was designed to support key/value, document, and graph data to be stored together, and queried via a unified language called AQL. The project is developed by ArangoDB GmbH, and released free and open-source under the Apache License 2.0. The universal "native multi-level" design of the database allows for a flexible approach when structuring and building an application, a feature that many have come to love.

CouchDB is a free and open-source document-oriented NoSQL database developed by the Apache Foundation. The database is written and implemented in the language Erlang and provides the use of multiple formats and protocols to store, transfer, and process data. With CouchDB you query data with JavaScript using MapReduce, and HTTP for an API. Which can be done across multiple distributed CouchDB instances as the database has the ability to synchronize multiple copies of the same database, across servers.