Apache Accumulo vs Apache Ignite

Apache Accumulo is a free, open-source sorted, distributed key/value store for storing and retrieving large datasets across a cluster. It uses Apache Hadoop HDFS for data storage and Apache ZooKeeper for consensus. Each key/value pair can carry a security label, so query results can be restricted according to a user’s authorizations. Accumulo Iterators can modify key/value pairs at different stages of data management. Clusters can use one or more HDFS instances, and nodes can be added or removed as stored data changes. The project says its client API follows Long Term Maintenance releases and semantic versioning, and that each release undergoes extensive testing. The software is licensed under Apache License, Version 2.0. The downloads page lists source and binary archives for versions 4.0.0-alpha-1, 3.0.0, and 2.1.6; the project identifies 4.0.0-alpha-1 as alpha and says alpha or beta releases are not production ready. General questions can go to the user mailing list, while the dev list serves contributor discussions. An interactive tour teaches the Java API through exercises and is designed for Accumulo 2.1.x or greater.

Apache Ignite is a free, open-source, memory-first distributed SQL database for high-velocity workloads. It keeps data primarily in memory, with persistence available through AIPERSIST, and supports ACID transactions across partitions using Raft consensus. MVCC snapshot isolation enables non-blocking reads. SQL access includes JDBC drivers, a Table API and native APIs, while catalog-driven schema management allows column and index changes without stopping the cluster. DataStreamer handles high-throughput writes with backpressure control. Native clients are listed for Java, .NET, C++ and Python, alongside AWS, Azure, GCE and Spring extensions. Built-in operational capabilities include authentication, SSL/TLS security, OpenTelemetry metrics, recovery snapshots and backups. Listed uses include event stream processing, microservices state management, session management and AI/ML feature stores. Ignite is self-hosted and available through binary, source, Docker and Maven/Gradle options. The project identifies Ignite 2 as a long-term-support release recommended for existing deployments.