Time Series Databases

InfluxDB31.6k★

InfluxDB is a time-series database built for metrics, events, and IoT data, handling millions of writes per second with built-in downsampling and retention policies. Regular databases can store time series data, but InfluxDB is optimized for high write throughput and fast range queries like "show me CPU usage for the last 24 hours." Apache 2.0, recently rewritten from Go to Rust (v3). The query language is SQL-compatible now (v3), dropping the custom InfluxQL and Flux languages from earlier versions. Handles millions of writes per second. Built-in downsampling, retention policies, and continuous queries. InfluxDB Cloud has a free tier: limited writes and queries, 30-day retention. Self-hosting is free with no feature restrictions. Cloud paid plans start at ~$0.002/MB written. Self-hosting v3 requires some infrastructure knowledge but isn't awful: single binary, configure storage. The ops burden is moderate: you need to manage retention policies, backups, and storage growth. Time series data accumulates fast. Solo: cloud free tier for prototyping, self-host for production. Small teams: self-host, $10-30/mo in compute. Medium to large: evaluate InfluxDB Cloud vs self-hosted ops cost. The catch: InfluxDB has gone through three major architecture rewrites (Go monolith → Go with TSM → Rust with Apache Arrow). Each version had a different query language and different trade-offs. The ecosystem documentation is fragmented; make sure you're reading v3 docs, not v1 or v2 guides.

TimescaleDB23.0k★

TimescaleDB is a Postgres extension that makes Postgres fast at time-series workloads: server metrics, IoT sensor readings, financial ticks, event logs. Not a separate database. An extension on top of Postgres. Your existing tools, ORMs, and knowledge all still work. C. The key feature: hypertables automatically partition your data by time, so queries like "average CPU usage over the last hour" are fast even on billions of rows. Continuous aggregates pre-compute rollups. Compression reduces storage by 90%+ for time-series data. The community edition is free and open source for self-hosting. Installs as a Postgres extension. If you can install extensions, you can run TimescaleDB. Timescale Cloud (managed Postgres with TimescaleDB) starts at $0.023/hr (~$17/mo) for a small instance. Scales based on compute and storage. They've rebranded to Tigerdata recently. Solo: self-host on your existing Postgres. Free. Small teams: self-host or Cloud at ~$17/mo to skip ops. Medium to large: evaluate Cloud vs self-hosted based on ops capacity. TimescaleDB is straightforward to self-host since it's just a Postgres extension. The catch: some advanced features (multi-node, certain compression options) were previously under a commercial license; the licensing has shifted over the years. Check the current Timescale License for your use case. And if your time-series workload is pure metrics with Prometheus-style queries, VictoriaMetrics or InfluxDB might be more purpose-built.