Redis Community Edition 8.0 release notes
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8.0-M04 (v7.9.227)    Committed Sun 16 Mar 2025 11:00:00 IST
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This is the fourth Milestone of Redis Community Edition 8.0.

Milestones are non-feature-complete pre-releases. Pre-releases are not suitable for production use.
Once we reach feature-completeness we will release RC1.

### Headlines

8.0-M04 includes 3 new hash commands, performance improvements, and memory defragmentation improvements.

### 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 and Debian APT - will be added on the GA release

### New Features

- #13798 Hash - new commands:
  - `HGETDEL` Get and delete the value of one or more fields of a given hash key
  - `HGETEX` Get the value of one or more fields of a given hash key, and optionally set their expiration
  - `HSETEX` Set the value of one or more fields of a given hash key, and optionally set their expiration
- #13773 Add replication offset to AOF, allowing more robust way to determine which AOF has a more up-to-date data during recovery
- #13740, #13763 shared secret - new mechanism to allow sending internal commands between nodes

### Bug fixes

- #13804 Overflow on 32-bit systems when calculating idle time for eviction
- #13793 `WAITAOF` returns prematurely
- #13800 Remove `DENYOOM` from `HEXPIRE`, `HEXPIREAT`, `HPEXPIRE`, and `HPEXPIREAT`
- #13632 Streams - wrong behavior of `XREAD +` after last entry

### Modules API

- #13788 `RedisModule_LoadDefaultConfigs` - load module configuration values from redis.conf
- #13815 `RM_RegisterDefragFunc2` - support for incremental defragmentation of global module data
- #13816 `RM_DefragRedisModuleDict` - allow modules to defrag `RedisModuleDict`
- #13774 `RM_GetContextFlags` - add a `REDISMODULE_CTX_FLAGS_DEBUG_ENABLED` flag to execute debug commands


### Performance and resource utilization improvements

- #13752 Reduce defrag CPU usage when defragmentation is ineffective
- #13764 Reduce latency when a command is called consecutively
- #13787 Optimize parsing data from clients, specifically multi-bulk (array) data
- #13792 Optimize dictionary lookup by avoiding duplicate key length calculation during comparisons
- #13796 Optimize expiration checks


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8.0-M03 (v7.9.226)    Committed Mon 20 Jan 2025 15:00:00 IST
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This is the third Milestone of Redis Community Edition 8.0.

Milestones are non-feature-complete pre-releases. Pre-releases are not suitable for production use.
Once we reach feature-completeness we will release RC1.

### Headlines:

8.0-M03 introduces an improved replication mechanism which is more performant and robust, a new I/O threading implementation which enables throughput increase on multi-core environments, and many additional performance improvements. Both Alpine and Debian Docker images are now available on [Docker Hub](https://hub.docker.com/_/redis). A snap and Homebrew distributions are available as well.


### Security fixes

- (CVE-2024-46981) Lua script may lead to remote code execution
- (CVE-2024-51741) Denial-of-service due to malformed ACL selectors

### New Features

- #13695 New I/O threading implementation 
- #13732 New replication mechanism


### Bug fixes

- #13653 `MODULE LOADEX` - crash on nonexistent parameter name
- #13661 `FUNCTION FLUSH` - memory leak when using jemalloc
- #13626 Memory leak on failed RDB loading

### Other general improvements

- #13639 When `hide-user-data-from-log` is enabled - also print command tokens on crash
- #13660 Add the Lua VM memory to memory overhead

### New metrics

- #13592 `INFO` - new `KEYSIZES` section includes key size distributions for basic data types
- #13695 `INFO` - new `Threads` section includes I/O threading metrics

### Modules API

- #13666 `RedisModule_ACLCheckKeyPrefixPermissions` - check access permissions to any key matching a given prefix
- #13676 `RedisModule_HashFieldMinExpire` - query the minimum expiration time over all the hash’s fields
- #13676 `RedisModule_HashGet` - new `REDISMODULE_HASH_EXPIRE_TIME` flag - query the field expiration time
- #13656 `RedisModule_RegisterXXXConfig` - allow registering unprefixed configuration parameters

### Configuration parameters


- `replica-full-sync-buffer-limit` - maximum size of accumulated replication stream data on the replica side
- `io-threads-do-reads` is no longer effective. The new I/O threading implementation always use threads for both reads and writes

### Performance and resource utilization improvements

- #13638 Optimize CRC64 performance
- #13521 Optimize commands with large argument count - reuse c->argv after command execution
- #13558 Optimize `PFCOUNT` and `PFMERGE` - SIMD acceleration
- #13644 Optimize `GET` on high pipeline use-cases
- #13646 Optimize `EXISTS` - prefetching and branch prediction hints
- #13652 Optimize `LRANGE` - improve listpack handling and decoding efficiency
- #13655 Optimize `HSET` - avoid unnecessary hash field creation or deletion
- #13721 Optimize `LRANGE` and `HGETALL` - refactor client write preparation and handling


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8.0-M02 (v7.9.225)    Committed Mon 28 Oct 2024 14:00:00 IST
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This is the second Milestone of Redis Community Edition 8.0.

Milestones are non-feature-complete pre-releases. Pre-releases are not suitable for production use.
Once we reach feature-completeness we will release RC1.

### Headlines:

8.0-M02 introduces significant performance improvements. Both Alpine and Debian Docker images are now available on [Docker Hub](https://hub.docker.com/_/redis). Additional distributions will be introduced in upcoming pre-releases.

### Supported upgrade paths (by replication or persistence) to 8.0-M02

- From previous Redis versions, without modules

The following upgrade paths (by replication or persistence) to 8.0-M02 are not yet tested and will be introduced in upcoming pre-releases:
- From previous Redis versions with modules (RediSearch, RedisJSON, RedisTimeSeries, RedisBloom)
- From Redis Stack 7.2 or 7.4

### Security fixes

- (CVE-2024-31449) Lua library commands may lead to stack overflow and potential RCE.
- (CVE-2024-31227) Potential Denial-of-service due to malformed ACL selectors.
- (CVE-2024-31228) Potential Denial-of-service due to unbounded pattern matching.

### Bug fixes

- #13539 Hash: Fix key ref for a hash that no longer has fields with expiration on `RENAME`/`MOVE`/`SWAPDB`/`RESTORE`
- #13512 Fix `TOUCH` command from a script in no-touch mode
- #13468 Cluster: Fix cluster node config corruption caused by mixing shard-id and non-shard-id versions
- #13608 Cluster: Fix `GET #` option in `SORT` command

### Modules API

- #13526 Extend `RedisModule_OpenKey` to read also expired keys and subkeys

### Performance and resource utilization improvements

- #11884 Optimize `ZADD` and `ZRANGE*` commands
- #13530 Optimize `SSCAN` command in case of listpack or intset encoding
- #13531 Optimize `HSCAN`/`ZSCAN` command in case of listpack encoding
- #13520 Optimize commands that heavily rely on bulk/mbulk replies (example of `LRANGE`)
- #13566 Optimize `ZUNION[STORE]` by avoiding redundant temporary dict usage
- #13567 Optimize `SUNION`/`SDIFF` commands by avoiding redundant temporary dict usage
- #11533 Avoid redundant `lpGet` to boost `quicklistCompare`
- #13412 Reduce redundant call of `prepareClientToWrite` when call `addReply*` continuously


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8.0-M01 (v7.9.224)    Released Thu 12 Sep 2024 10:00:00 IST
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This is the first Milestone of Redis Community Edition 8.0.

Milestones are non-feature-complete pre-releases. Pre-releases are not suitable for production use.
Once we reach feature-completeness we will release RC1.

### Headlines:

Redis 8.0 introduces new data structures: JSON, time series, and 5 probabilistic data structures (previously available as separate Redis modules) and incorporates the enhanced Redis Query Enginer (with vector search).

8.0-M01 is available as a Docker image and can be downloaded from [Docker Hub](https://hub.docker.com/_/redis). Additional distributions will be introduced in upcoming pre-releases.

### Supported upgrade paths (by replication or persistence) to 8.0-M01


- From previous Redis versions, without modules

The following upgrade paths (by replication or persistence) to 8.0-M01 are not yet tested and will be introduced in upcoming pre-releases:
- From previous Redis versions with modules (RediSearch, RedisJSON, RedisTimeSeries, RedisBloom)
- From Redis Stack 7.2 or 7.4

### New Features in binary distributions

- 7 new data structures: JSON, Time series, Bloom filter, Cuckoo filter, Count-min sketch, Top-k, t-digest
- The enhanced Redis Query Engine (with vector search)

### Potentially breaking changes

- #12272 `GETRANGE` returns an empty bulk when the negative end index is out of range
- #12395 Optimize `SCAN` command when matching data type

### Bug fixes

- #13510 Fix `RM_RdbLoad` to enable AOF after RDB loading is completed
- #13489 `ACL CAT` - return module commands
- #13476 Fix a race condition in the `cache_memory` of `functionsLibCtx`
- #13473 Fix incorrect lag due to trimming stream via `XTRIM` command
- #13338 Fix incorrect lag field in `XINFO` when tombstone is after the `last_id` of the consume group
- #13470 On `HDEL` of last field - update the global hash field expiration data structure
- #13465 Cluster: Pass extensions to node if extension processing is handled by it
- #13443 Cluster: Ensure validity of myself when loading cluster config
- #13422 Cluster: Fix `CLUSTER SHARDS` command returns empty array

### Modules API

- #13509 New API calls: `RM_DefragAllocRaw`, `RM_DefragFreeRaw`, and `RM_RegisterDefragCallbacks` - defrag API to allocate and free raw memory

### Performance and resource utilization improvements

- #13503 Avoid overhead of comparison function pointer calls in listpack `lpFind`
- #13505 Optimize `STRING` datatype write commands
- #13499 Optimize `SMEMBERS` command
- #13494 Optimize `GEO*` commands reply
- #13490 Optimize `HELLO` command
- #13488 Optimize client query buffer
- #12395 Optimize `SCAN` command when matching data type
- #13529 Optimize `LREM`, `LPOS`, `LINSERT`, and `LINDEX` commands
- #13516 Optimize `LRANGE` and other commands that perform several writes to client buffers per call
- #13431 Avoid `used_memory` contention when updating from multiple threads

### Other general improvements

- #13495 Reply `-LOADING` on replica while flushing the db

### CLI tools

- #13411 redis-cli: Fix wrong `dbnum` showed after the client reconnected

### Notes

- No backward compatibility for replication or persistence.
- Additional distributions, upgrade paths, features, and improvements will be introduced in upcoming pre-releases.
- With the GA release of 8.0 we will deprecate Redis Stack.