Redis is an in-memory key-value database used for caching, queues/streams, session storage, and low-latency state access.
- High-throughput cache layers
- Real-time counters, rate limits, and ephemeral state
- Stream and pub/sub style event workflows
- Time series data storage
- Hot keys detection and analysis
- In-memory data structures (strings, hashes, sets, sorted sets, streams, bitmaps, hyperloglogs)
- Advanced data types (JSON, Search, Graph, Timeseries, Bloom filters, Cuckoo filters)
- Persistence options (RDB snapshots and AOF with RDB preambles)
- Replication and Sentinel/Cluster deployment models
- Large ecosystem integrations for web and API stacks
- Substantial performance improvements in recent versions
- Memory reduction optimizations for hashes and sorted sets
- XADD idempotency for streams (at-most-once guarantee)
- New eviction policies: volatile-lrm and allkeys-lrm
- TLS certificate-based automatic client authentication
- C
- Lua scripting engine
- Built with CMake (version 3.31.6 is latest supported)
- Latest Version: 8.6.0 (Released February 10, 2025)
- Recent Stable: 7.4.x series (Still widely deployed)
- Previous Stable: 6.2.x series (Extended support)
- Current: Dual source-available licensing (RSALv2 + SSPLv1) for versions 7.4+
- Historical: BSD 3-clause license for versions 7.2 and earlier
- Note: Redis is no longer considered open source under OSI definition as of March 20, 2024
- Redis Community Edition: Free to use for individuals and internal enterprise use
- Active project with frequent updates
- Common component in performance-sensitive Linux architectures
- License change impacts cloud service providers and competitive offerings
- Consider Valkey as a community-driven open-source alternative
- Performance Improvements: Substantial performance gains over previous versions
- Memory Reduction: Optimized memory usage for hashes and sorted sets
- XADD Idempotency: New IDMPAUTO and IDMP arguments for at-most-once guarantee in streams
- New Eviction Policies:
volatile-lrm and allkeys-lrm for least recently modified keys
- Hot Keys Detection: New
HOTKEYS command for identifying frequently accessed keys
- TLS Certificate-Based Authentication: Enhanced security for client authentication
- Time Series Enhancements: Support for NaN values and new aggregators (COUNTNAN, COUNTALL)
- License Change: Redis 7.4+ uses RSALv2/SSPLv1 licenses instead of BSD
- Feature Adoption: Plan to utilize new features like hot keys detection and improved eviction policies
- Testing: Thoroughly test applications with new Redis versions in staging before production deployment
- Backup Strategy: Ensure backup and recovery procedures work with new version formats
- From Redis 7.2: Most configurations will work without changes
- ACL Improvements: Take advantage of optimized user ACL permission verification
- Memory Optimization: Adjust
maxmemory settings based on improved memory efficiency
- Monitoring: Enable new latency monitoring features for better performance insights
¶ History and References