8.8-m02

This is the second Milestone of Redis 8.8 in Redis Open Source.

Milestones are non-feature-complete pre-releases. Pre-releases are not suitable for production use.

Headlines:

Redis 8.8 introduces new features and performance improvements.

8.8-M02 is available as a Docker image and can be downloaded from Docker Hub. Additional distributions will be introduced in upcoming pre-releases.

Operating systems we test Redis 8.8 on

• Ubuntu 22.04 (Jammy Jellyfish), 24.04 (Noble Numbat), 26.04 (Resolute Raccoon)
• Rocky Linux 8.10, 9.7, 10.1
• AlmaLinux 8.10, 9.7, 10.1
• Debian 12.13 (Bookworm), Debian 13.4 (Trixie)
• Alpine 3.23
• macOS 14.8.4 (Sonoma), 15.7.4 (Sequoia), 26.3 (Tahoe) - for both Intel and ARM

New Features (compared to 8.6)

• #14826, #14905 GCRA (generic cell rate algorithm) rate limiter (based on the redis-cell module by @brandur - thank you!)
• #14797 XNACK: a new streams command that allows consumers to explicitly release pending messages
• RedisJSON/RedisJSON#1509 JSON.SET: new FPHA argument to specify the FP type for FP homogeneous arrays (MOD-13577)
• #14892 ZUNION, ZINTER, ZUNIONSTORE, ZINTERSTORE: new COUNT aggregator
• RedisTimeSeries/RedisTimeSeries#1916 TS.RANGE, TS.REVRANGE, TS.MRANGE, TS.MREVRANGE: multiple aggregators in a single command (MOD-9162)

Bug fixes (compared to 8.6.2)

• #15037 XINFO STREAM: wrong value in the per-slot memory tracking
• #12000 Incorrect shrinking of querybuf when client is reading a big argv
• #15021 HEXPIRE: overflow on fields count
• #14963 XREADGROUP: consumer replication inconsistency
• #15011 Double-free in rdbLoadObject
• #14667, #14886 Potential TCP stalls/deadlocks
• #14942 Fix COMMAND GETKEYS for PFMERGE with no source keys
• #14888 Hardens safety check in lpSafeToAdd
• #14748 Ensure sensitive user data is not exposed in logs when hide_user_data_from_log is enabled
• #14877 INFO KEYSIZES and INFO ALLOCSIZES fixes
• #14878 listpack memory leak in zipmap-to-hash conversion on error path
• #14955 Streams: IDMP-related bug
• #14974, #14932, #14866 Memory leaks
• #14790 Missing initialization
• #14789 DB hash tables not expanding during RDB load on standalone-mode
• #14785 Add HOTKEYS HELP subcommand (Each command having subcommands needs a HELP subcommand)
• #14784 RESTORE and SET: expiredkeys counter updates incorrectly on keys with past expiration time
• #14779 Accurate memory accounting for RedisModuleDict (instead of estimation)
• #14774 Missing cleanup code in getKeysFreeResult() on cross-slot error path
• #14771 Potential unsigned integer underflow in used_memory_dataset calculation
• #14780 Fixed name of HOTKEYS results field sampled-command-selected-slots-us to sampled-commands-selected-slots-us
• #14756 HOTKEYS does not track each command in a MULTI/EXEC block
• #14749 Fixed HOTKEYS GET RESP3 reply fixed to map instead of flat array
• RedisJSON/RedisJSON#1520 Numeric operations on homogeneous arrays: promote to next type if results overflow (MOD-14427)
• RedisJSON/RedisJSON#1519 JSON.NUMINCRBY, JSON.NUMMULTBY don’t error on numeric overflow (MOD-14191)
• RedisJSON/RedisJSON#1487 Depth limit (128) was not fully enforced (MOD-4107)
• RedisTimeSeries/RedisTimeSeries#1910 TS.INCRBY, TS.DECRBY create key before validating args (MOD-8167)
• RedisTimeSeries/RedisTimeSeries#1908 Potential crash on TS.RANGE with aggregation and EMPTY
• RedisTimeSeries/RedisTimeSeries#1896 Potential memory leak (MOD-13438)
• RedisTimeSeries/RedisTimeSeries#1913 ACL rules are not fully enforced for multi-key commands on a cluster setup (MOD-14124)

Performance and resource utilization improvements (compared to 8.6.2)

• #15003 Reduce overhead in command propagation
• #14979 Dismiss dict bucket arrays in fork child to reduce CoW
• #14661 Replace fast_float C++ library with pure C implementation
• #14928 Disable memory tracking in child processes
• #14885 Optimize rax (radix tree) insert and lookup for sequential key patterns
• #14335 Handle primary/replica clients in I/O threads
• #14754 Optimize prefetching commands
• #14770 Optimize BITOP operations with AVX512
• #14862 Streams: Filter expired IDMP entries during RDB save and load
• #14750 SFLUSH can now flush slots partially
• #14887 SFLUSH skips slot trimming when the requested slot ranges exactly match the node’s local slot coverage
• #14851 Skip RDB checksum computation/validation during diskless full synchronization to reduce CPU overhead
• #14783 Pause dict auto-resize during multi-field deletion
• RedisTimeSeries/RedisTimeSeries#1884 TS.RANGE, TS.REVRANGE, TS.MRANGE, TS.MREVRANGE: improve performance on a cluster setup (RED-184104)
• RedisTimeSeries/RedisTimeSeries#1866 Register to type_changed KSN instead of set (MOD-12919)

Modules API

• #14445 Allow modules to associate metadata with keys
  • RedisModule_CreateKeyMetaClass - define a new key-metadata class
  • RedisModule_ReleaseKeyMetaClass - release a key-metadata class
  • RedisModule_SetModuleMetadata - attach or update metadata to a key
  • RedisModule_GetKeyMeta - get key metadata

Metrics

• #14896 INFO STATS - global stats for slowlog metrics:
  • slowlog_commands_count - commands written to slowlog
  • slowlog_commands_time_ms_sum - sum of execution times of commands from the slowlog
  • slowlog_commands_time_ms_max - maximum execution time of a command from the slowlog
• #14896 INFO COMMANDSTATS - per-command stats for slowlog metrics:
  • slowlog_count - number of times the command was written in the slowlog
  • slowlog_time_ms_sum - sum of execution time of the command (only from the slowlog)
  • slowlog_time_ms_max - maximum execution time of the command (only from the slowlog)
• #14841 INFO STATS (global, all clients aggregated):
  • total_client_processing_events: attempts to process client input buffers; does not guarantee any command was actually parsed
  • eventloop_cycles_with_clients_processing: event loop cycles where client input buffers were processed
  • commands_per_parse_batch_sum: cumulative number of commands parsed across all parsing batches for all clients
  • commands_per_parse_batch_cnt: number of parsing batches across all clients. A batch is counted each time at least one command is parsed from a client's query buffer
  • commands_per_parse_batch_avg: average commands parsed per batch (sum/cnt). Approximates pipelining depth
• #14841 CLIENT INFO and CLIENT LIST (per-client):
  • read-events: number of read events for this client
  • parse-batch-cmd-sum: cumulative number of commands parsed across all parsing batches for this client
  • parse-batch-cnt: total number of parsing batches for this client. Divide parse-batch-cmd-sum by this value to get the client’s average commands per batch

CLI tools

• #14371 Divide-by-zero in redis-benchmark and redis-cli
• #14863 Memory leak in redis-cli
• #14703 redis-cli --keystats: fix percentile calculation