CnosDB vs QuestDB

CnosDB is an open-source distributed time-series database for workloads such as IoT, industrial internet, connected vehicles, and IT operations. It supports standard SQL, time-based aggregation, and a DataFrame API. Data can be written without a predefined schema, including out of order, and historical data can be replenished. Ingestion methods include SQL, Line Protocol, OpenTSDB, Elasticsearch bulk, Loki, NDJSON, and OpenTelemetry. Deployment options include standalone, distributed, and storage-compute separated modes, on public, private, or hybrid clouds. The documentation describes horizontal scaling for storage and stateless compute nodes. Integrations include Grafana, Prometheus, Telegraf, JDBC, and a Python SDK; the open-source Python connector provides a PEP 249 interface for SQLAlchemy and pandas. Import and export formats include PARQUET, CSV, and JSON with AWS S3, Google Cloud Storage, and Azure Blob Storage. CnosDB documents retention policies, multi-tenancy, and role-based permissions, as well as optional TLS certificate and private-key settings. Community Edition is free under AGPL-3.0.

QuestDB is a time-series database for environments where low latency matters, including mission-critical workloads. It supports standard SQL through a vectorized execution engine, along with time-series extensions such as SAMPLE BY, ASOF, and HORIZON JOIN. QuestDB advertises ingestion speeds of 8M+ rows per second. The Open Source edition is self-managed and available as binaries, containers, or source code; it is single-instance and supports Parquet storage and PostgreSQL Wire Protocol compatibility. Ingestion options include QuestDB Wire Protocol, InfluxDB Line Protocol, REST API, native client libraries, SQL INSERT, Kafka connector, and CSV import. Listed integrations include Grafana, Power BI, Apache Kafka, Telegraf, Redpanda, Apache Flink, Pandas, and Apache Spark. Open Source costs nothing and includes community support. Enterprise adds security controls, replication, automatic failover, object-storage tables, and dedicated support with response-time SLAs.