CnosDB vs kdb+

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.

kdb+ is a time-series database and analytics engine from KX, built around the q vector language. It captures and analyzes real-time and historical data for time-sensitive workloads. KX describes in-memory ingestion and analysis with sub-millisecond performance. Its storage layout separates newest in-memory records in an RDB, recent disk data in an IDB, and long-term columnar archives in an HDB. Query options include q and q-SQL, with support for Python, Java, C#, C++, Rust, R, and open-source libraries. Data can arrive through tickerplants, feed handlers, batch mode, TCP/IP, Apache Kafka, or supported programming languages. KX describes applications in trading, fraud detection, and IoT monitoring across Capital Markets, Defense, and High-Tech Manufacturing. Deployments cover Linux, macOS, Windows, APIs, and self-hosted environments, with cloud documentation for AWS, Google Cloud Platform, and Microsoft Azure. SSL/TLS connections use OpenSSL certificates and keys.