reddis

Reddis is commonly a misspelling of Redis, the open-source in-memory data structure store used as a database, cache, and message broker. Redis was created by Salvatore Sanfilippo (also known as antirez) and first released in 2009. It is now maintained by Redis Ltd. and community contributors and is widely adopted in the software industry.

Redis stores data as key-value pairs in a variety of data structures, including strings, lists, sets, sorted sets, hashes, and streams. It supports transactions, Lua scripting, publish/subscribe, and high-level constructs like hyperloglog, bitmaps, and geospatial indexes.

Persistence and durability: Redis provides optional on-disk persistence through RDB snapshots and the Append Only File (AOF) log, with configurable durability trade-offs. It can replicate data to one or more replicas and supports Redis Cluster for sharded deployments and Redis Sentinel for high availability. It is designed for high performance with sub-millisecond latency on typical operations.

Architecture and usage: Redis uses an in-memory dataset with a loop that processes commands. In recent versions, there is optional multi-threaded I/O to reduce network overhead while keeping the core single-threaded command execution. Clients are available for many programming languages. Common use cases include caching, session storage, real-time analytics, message brokering via pub/sub, and as a fast data store for applications.

Licensing and ecosystem: Redis is distributed under a BSD-style license. The ecosystem includes Redis Modules that extend functionality (for example, RediSearch, RedisGraph), client libraries, and managed services offered by cloud providers.