QuestDB

QuestDB is an open-source time-series database built for high-throughput ingestion and real-time analytics. It uses a columnar storage model with SIMD-optimized queries and supports standard SQL with time-series extensions. The database is written in Java with performance-critical paths in C++.

What it does

QuestDB ingests time-series data through multiple protocols including InfluxDB line protocol, PostgreSQL wire protocol, and a REST API. It stores data in a columnar format optimized for time-range queries and aggregation. The query engine supports standard SQL with extensions for time-series operations like SAMPLE BY for downsampling and LATEST ON for last-value queries.

Key features

• SQL support with time-series extensions (SAMPLE BY, LATEST ON, ASOF JOIN)
• InfluxDB line protocol compatibility for easy migration
• PostgreSQL wire protocol for tool compatibility
• SIMD-optimized query execution
• Relational joins between time-series and relational data
• Grafana integration via PostgreSQL data source
• High ingestion throughput (millions of rows per second on commodity hardware)

Deployment options

QuestDB runs as a single binary with no external dependencies. Deployment options include Docker containers, Kubernetes, cloud instances, or bare metal. The database supports replication for high availability in the enterprise edition.

Limitations

• Open-source version lacks built-in clustering and replication features, requiring enterprise license for high-availability deployments
• Smaller ecosystem compared to InfluxDB or TimescaleDB, with fewer third-party integrations and community plugins
• Limited built-in data retention policies compared to specialized competitors; requires manual configuration for automated downsampling and expiration
• Java-based runtime requires JVM tuning for predictable latency in high-throughput scenarios
• Query optimization is less mature than PostgreSQL for complex analytical workloads with many joins