This is the first Release Candidate of Redis 8.6 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 8.6 on

• Ubuntu 22.04 (Jammy Jellyfish), 24.04 (Noble Numbat)
• Rocky Linux 8.10, 9.5, 10.1
• AlmaLinux 8.10, 9.5, 10.1
• Debian 12 (Bookworm), Debian 13 (Trixie)
• 14 (Sonoma), 15 (Sequoia)

New Features (compared to 8.4.0)

• #14615 Streams: XADD idempotency (at-most-once guarantee) with new IDMPAUTO and IDMP arguments
• #14624 New eviction policies - least recently modified: volatile-lrm and allkeys-lrm
• #14680 Hot keys detection and reporting; new command: HOTKEYS
• #14610 TLS certificate-based automatic client authentication
• RedisTimeSeries/RedisTimeSeries#1853 Time series: support NaN values; new aggregators: COUNTNAN and COUNTALL

Security and privacy fixes

• #14645 Hide Personally Identifiable Information from ACL log
• #14659 ACL: Key-pattern bypass in MSETEX
• RedisTimeSeries/RedisTimeSeries#1837, RedisJSON/RedisJSON#1474 Hide Personally Identifiable Information from server log
• RedisBloom/RedisBloom#950 Out-of-bounds read when loading an invalid RDB file (MOD-12802)

Bug fixes (compared to 8.4.0)

• #14545 ACL: AOF loading fails if ACL rules are changed and don't allow some commands in MULTI-EXEC
• #14637 Atomic slot migration: wrong adjacent slot range behavior
• #14567 Atomic slot migration: support delay trimming slots after finishing migrating slots
• #14623 Streams: XTRIM/XADD with approx mode (~) don’t delete entries for DELREF/ACKED strategies
• #14552 Streams: Incorrect behavior when using XDELEX...ACKEDafterXGROUP DESTROY`
• #14537 SCAN: restore original filter order (revert change introduced in 8.2)
• #14581 Rare server hang at shutdown
• #14597 Panic when cluster node is uninitialized
• #14583 FLUSHALL ASYNC on a writable replica may block the main thread for an extended period
• #14504 Cluster: fix race condition in broadcast configuration
• #14416 Fixed argument position handling in Redis APIs
• RedisTimeSeries/RedisTimeSeries#1784, RedisTimeSeries/RedisTimeSeries#1839, RedisBloom/RedisBloom#952, RedisJSON/RedisJSON#1477 Atomic slot migration support
• RedisBloom/RedisBloom#946 MEMORY USAGE: fix reported value (MOD-12799)
• RedisJSON/RedisJSON#1473 Adding escapes to already-escaped characters (MOD-8137)
• RedisJSON/RedisJSON#1475 JSON.CLEAR does not error if more than one path is specified (MOD-13109)

Performance and resource utilization improvements (compared to 8.4.0)

• #14608 Reply copy-avoidance path to reduce memory copies for bulk string replies
• #14595 Hash: unify field name and value into a single struct
• #14701 Sorted set: unify score and value into a single struct
• #14662 Optimize listpack iterator on hash fields
• #14699 Optimize set commands with expiration
• #14700 Optimize prefetching
• #14715 Optimize prefetch sizing logic
• #14636 Optimize ZRANK
• #14676 Utilize hardware clock by default on ARM AArch64
• #14575 Disable RDB compression when diskless replication is used

Modules API

• #14445
  • RM_CreateKeyMetaClass - define a new key-metadata class
  • RM_ReleaseKeyMetaClass - release a key-metadata class
  • RM_SetKeyMeta - attach or update a metadata value for a key under a specific metadata-key class
  • RM_GetKeyMeta - get a metadata value for a key under a specific metadata-key class

Configuration parameters

• #14624 maxmemory-policy: new eviction policies: volatile-lrm, allkeys-lrm
• #14615 stream-idmp-duration, stream-idmp-maxsize - defaults for streams idempotent production
• #14610 tls-auth-clients-user TLS certificate-based automatic client authentication
• #14596 flushdb option for repl-diskless-load: always flush the entire dataset before diskless load

Metrics

• #14610 acl_access_denied_tls_cert - failed TLS certificate–based authentication attempts

known bugs and limitations

• Redis Query Engine: In case of load rebalancing operations (such as Atomic Slot Migration) taking place during the lifetime of a cursor, there is a chance that some results may be missing.