Apache AsterixDB vs Azure Cosmos DB for NoSQL

Apache AsterixDB is a free, open source, self-managed Big Data Management System for ingesting, storing, indexing, querying and analyzing data. Its Asterix Data Model extends JSON with object-database concepts, while SQL++ and AQL provide declarative queries for semistructured information. Partitioned LSM-based storage supports B+ tree, R-tree and inverted keyword secondary indexes. External datasets can be queried without loading everything into AsterixDB, using adapters for HDFS and local filesystems. Continuous feeds can ingest sources such as Twitter, RSS and sockets. The HTTP query API accepts SQL++ and can return immediate, deferred or asynchronous results. Installation options include NCService, Ansible and Amazon Web Services. The Hyracks parallel runtime has been scale-tested on up to 1000+ cores and 500+ disks. Documentation describes basic transactional concurrency and recovery, and identifies web data warehousing and social data analysis as suitable uses.

Azure Cosmos DB for NoSQL is a fully managed cloud database built around schema-agnostic JSON documents and SQL-like querying. It supports global data distribution, multi-region writes, and automatic failover, with configurable consistency controls and transactions. Search includes vector and hybrid similarity capabilities for workloads such as retrieval-augmented generation and AI agents. Throughput can use standard provisioned, autoscale provisioned, or serverless models. The service lists SDKs for.NET, Java, JavaScript/Node.js, Python, Go, and Rust. Its change feed can support event-driven architectures and streaming pipelines using Azure Functions and Spark; no-ETL analytical workflows are available through Azure Synapse Link or Fabric mirroring. Microsoft states that NoSQL data has service-level agreements including less than 10 millisecond read and write latency and 99.999 percent availability. A free tier includes 1,000 RU/s and 25 GB of storage for one account per Azure subscription, and a 30-day trial is listed. The Azure Cosmos DB emulator provides a no-cost local development environment for Windows or Linux. The pricing page notes that the selected compute pricing model and API cannot be changed after selection.