Kdb+ vs GridDB: What are the differences?
Kdb+: Fast, powerful, massively scalable time-series database. It is a column-based relational time-series database with in-memory abilities. The database is commonly used in high-frequency trading to store, analyze, process, and retrieve large data sets at high speed. kdb+ has the ability to handle billions of records and analyzes data within a database; GridDB: Open source time series database for IoT and Big Data. It is a highly scalable, in-memory NoSQL time series database optimized for IoT and Big Data. It has a KVS (Key-Value Store)-type data model that is suitable for sensor data stored in a timeseries. It is a database that can be easily scaled-out according to the number of sensors.
Kdb+ and GridDB belong to "In-Memory Databases" category of the tech stack.