InfluxDB
Developed in go language, InfluxDB is a Time Series database with very interesting performances and data compression.
Data ingestion is easy to implement and its integration into reporting tools like Grafana very mature.
InfluxDB v2, Flux language and SQL databases March 8th, 2021
sql.from and sql.to
Use cases and specific considerations about data types conversions.
  InfluxDB - Flux language, advanced features March 1st, 2021
InfluxDB v2 : Flux language, quick reference guide and cheat sheet February 19th, 2021
InfluxDB - Moving from InfluxQL to Flux language February 5th, 2021
InfluxDB - Migration to version 2 February 1st, 2021
- A database + retention policy is a bucket in version 2.
 - Backward compatibility with 1.x API is guaranteed, but only for authenticated 1.x users.
 - Continuous queries must be migrated to Flux tasks.
 - InfluQL is replaced by Flux language.
 - Native support of OpenTSDB, Graphite… protocols is removed, Telegraf must be implemented.