Need: Since InfluxDB has a free tier to retain data for 30 days only, a quick research on alternate databases that can be used is summarized below.

Note: Images snipped from respective websites

Primary Criteria

1. Should preferably be a time series database, or a database that can handle time series data
2. Preferably open source, or database with better free tier
3. Community support
4. Learning curve
5. Integration with plotly/dash - I don’t see this as a strong requirement, as I think we can always develop the charts we have today in any other tool (eg., d3.js or any such thing that the db supports) if required

Choices considered

QuestDB

Prometheus

Apache Druid

GridDB

OpenTSDB

Apache Cassandra

A quick brief

QuestDB (Open source) - https://questdb.io/

1. Fast SQL for time series
2. Installation is possible through docker images as well as binaries (require java 11)
3. SQL is used for DDL and DML commands, no database specific query language is required