This is the first Release Candidate of Redis 8.4 in Redis Open Source.

Release Candidates are feature-complete pre-releases. Pre-releases are not suitable for production use.

Binary distributions

• Alpine and Debian Docker images - https://hub.docker.com/_/redis
• Install using snap - see https://github.com/redis/redis-snap
• Install using brew - see https://github.com/redis/homebrew-redis
• Install using RPM - see https://github.com/redis/redis-rpm
• Install using Debian APT - see https://github.com/redis/redis-debian

Operating systems we test Redis 8.4 on

• Ubuntu 22.04 (Jammy Jellyfish), 24.04 (Noble Numbat)
• Rocky Linux 8.10, 9.5
• AlmaLinux 8.10, 9.5
• Debian 12 (Bookworm), Debian 13 (Trixie)
• macOS 13 (Ventura), 14 (Sonoma), 15 (Sequoia)

New Features (compared to 8.2.3)

• #14414 New command: CLUSTER MIGRATION - atomic slot migration
• #14435 New commands: DELEX, DIGEST; SET extensions - atomic compare-and-set and compare-and-delete for string keys
• #14434 New command: MSETEX - set multiple keys and update their expiration
• #14402 XREADGROUP - add CLAIM min-idle-time to consume both idle pending entries and incoming entries
• #14058 Add auto-repair options for broken AOF tail on startup
• #14296 Support decoding JSON empty array as a Lua array
• RedisTimeSeries/RedisTimeSeries#1773 HELP and COMMAND DOCS now support time series commands (MOD-8133)
• RedisBloom/RedisBloom#892 HELP and COMMAND DOCS now support probabilistic commands (MOD-8133)
• RediSearch/RediSearch#7076, RediSearch/RediSearch#6857 New Command: FT.HYBRID - hybrid queries with RRF and LINEAR combination
• RediSearch/RediSearch#7022 Support index updates when atomic slot migrations occur
• RediSearch/RediSearch#6313 Support multiple I/O threads for RQE cluster manager - Coordinator (MOD-10562)

Bug fixes (compared to 8.2.3)

• #14423 Potential infinite loop when a stream is corrupted
• #14420 Shutdown blocked client not being properly reset after shutdown cancellation
• #14417 CLUSTER FORGET - heap-buffer-overflow
• #14415 Potential crash in lookupKey() when executing_client is NULL
• RedisTimeSeries/RedisTimeSeries#1776 Potential crash on TS.RANGE with ALIGN +, AGGREGATION twa and EMPTY (MOD-11620, MOD-10484)

Performance and resource utilization improvements (compared to 8.2.3)

• #14440 Lookahead prefetching - parse multiple commands in advance through a lookahead pipeline
• #14309 Optimize BITCOUNT with AVX2 and AVX512 popcount implementations
• #14227 Optimize BITCOUNT with Arm Neon SIMD vectorization
• #14428 Optimize HyperLogLog with branchless comparisons and Arm Neon SIMD vectorization
• #14222 Optimize Vector set VADD and VSIM with AVX2 and AVX512 dot product implementations
• RedisJSON/ijson#9 JSON - memory footprint improvement by using homogeneous arrays (MOD-9511)
• RedisJSON/ijson#7 JSON - memory footprint improvement by inlining short strings (MOD-9511)

Configuration parameters

• #14058 aof-load-corrupt-tail-max-size - maximum corrupted tail size (in bytes) to attempt to repair automatically
• #14296 decode_array_with_array_mt - Lua: control how empty JSON arrays are handled
• #14440 lookahead - runtime-configurable lookahead depth (default: 16)
• RediSearch/RediSearch#7065 search-default-scorer - default text and tag scorer (new default is BM25STD)
• RediSearch/RediSearch#6769 search-on-oom - behavior when OOM event occurs in the query time, supports 3 values:
  • IGNORE - queries run despite OOM, not recommended for heavy result sets (current behaviour)
  • FAIL - query execution fails if any node is in OOM state at start
  • RETURN - returns partial results if OOM is detected in only some cluster nodes (default)
• RediSearch/RediSearch#6313 search-io-threads - allow setting the comms threads used by the cluster manager - coordinator (default: 20)

known bugs and limitations

• When executing FT.SEARCH, FT.AGGREGATE, FT.CURSOR, FT.HYBRID, TS.MGET, TS.MRANGE, TS.MREVRANGE and TS.QUERYINDEX while an atomic slot migration process is in progress, the results may be partial or contain duplicates
• FT.PROFILE, FT.EXPLAIN and FT.EXPLACINCLI don’t contain the FT.HYBRID option
• Metrics from FT.HYBRID command aren’t displayed on FT.INFO and INFO
• Option EXPLAINSCORE, SHARD_K_RATIO, YIELD_DISTANCE_AS, and WITHCURSOR with FT.HYBRID are not available
• Post-filtering (after COMBINE step) using FILTER is not available
• Currently, the default response format considers only key_id and score, this may change for delivering the entire document content