DEV: add 8.6 what's new page

content/develop/whats-new/8-6.md

@@ -0,0 +1,123 @@
+---
+title: Redis 8.6
+alwaysopen: false
+categories:
+- docs
+- operate
+- rs
+- rc
+description: What's new in Redis 8.6
+linkTitle: What's new in Redis 8.6
+weight: 2
+---
+
+Redis 8.6 builds on the foundation of Redis 8.4 with significant enhancements to stream reliability, memory management, and security features.
+
+This release delivers major improvements across multiple areas:
+- Stream idempotency with at-most-once delivery guarantees.
+- New eviction policies for least recently modified data.
+- Hot key detection and reporting capabilities.
+- TLS certificate-based automatic client authentication.
+- Enhanced time series support with NaN values and new aggregators.
+- More than 15 performance and resource utilization improvements.
+
+Below is a detailed breakdown of these updates.
+
+## Security improvements
+
+Redis 8.6 includes important security and privacy enhancements:
+- **Privacy protection**: Personally identifiable information is now hidden from ACL logs and server logs across Redis core and modules.
+- **ACL security fix**: Fixed key-pattern bypass vulnerability in `MSETEX` command.
+- **Module security**: Addressed out-of-bounds read vulnerability when loading invalid RDB files in RedisBloom.
+
+## New features
+
+### Stream idempotency
+
+Redis 8.6 introduces powerful idempotency features for [Redis Streams]({{< relref "/develop/data-types/streams/" >}}) that provide at-most-once delivery guarantees:
+
+- **IDMPAUTO argument**: Automatically generates idempotent identifiers for `XADD` operations.
+- **IDMP argument**: Allows manual specification of idempotent identifiers.
+
+These features prevent duplicate entries in streams, making Redis Streams more reliable for critical data processing pipelines where duplicate processing could cause issues.
+
+### Enhanced memory management
+
+Redis 8.6 introduces new [eviction policies]({{< relref "/develop/reference/eviction/" >}}) that provide more granular control over memory management:
+
+- **volatile-lrm**: Evicts keys with expiration times based on least recently modified criteria.
+- **allkeys-lrm**: Evicts any keys based on least recently modified criteria.
+
+These policies complement existing LRU (Least Recently Used) policies by focusing on modification patterns rather than access patterns, providing better control for write-heavy workloads.
+
+### Hot key detection
+
+The new [`HOTKEYS`]({{< relref "/commands/hotkeys/" >}}) commands enable real-time detection and reporting of frequently accessed keys. This feature helps identify performance bottlenecks and optimize data distribution in clustered environments.
+
+### TLS certificate-based authentication
+
+Redis 8.6 introduces automatic client authentication using TLS certificates. This feature streamlines secure connections by automatically mapping TLS certificates to Redis users, reducing the need for password-based authentication in certificate-enabled environments.
+
+### Enhanced time series capabilities
+
+Redis 8.6 extends [time series]({{< relref "/develop/data-types/timeseries/" >}}) functionality with:
+
+- **NaN value support**: Time series can now store and process Not-a-Number values for incomplete or invalid data points.
+- **New aggregators**: `COUNTNAN` and `COUNTALL` aggregators provide better analytics for datasets containing NaN values.
+
+## Improvements
+
+Redis 8.6 delivers substantial performance improvements across core operations and data structures.
+
+### Performance optimizations
+
+- **Reply optimization**: Copy-avoidance path reduces memory copies for bulk string replies.
+- **Data structure improvements**: Hash and sorted set operations benefit from unified field/value and score/value structures.
+- **Iterator optimization**: Improved listpack iterator performance for hash field operations.
+- **Command optimization**: Enhanced `ZRANK` performance and optimized set commands with expiration.
+- **Prefetching enhancements**: Improved prefetching logic and sizing algorithms.
+- **Hardware utilization**: ARM AArch64 systems now utilize hardware clocks by default for better performance.
+
+### Replication improvements
+
+- **Diskless replication**: RDB compression is now disabled during diskless replication to improve transfer speeds.
+- **Configuration flexibility**: New `flushdb` option for `repl-diskless-load` provides better control over dataset handling during replication.
+
+## Configuration enhancements
+
+Redis 8.6 introduces new configuration parameters that provide greater control over system behavior:
+
+- **Stream idempotency**: `stream-idmp-duration` and `stream-idmp-maxsize` control default settings for idempotent stream production.
+- **TLS authentication**: `tls-auth-clients-user` enables certificate-based automatic client authentication.
+- **Memory policies**: Support for new `volatile-lrm` and `allkeys-lrm` eviction policies.
+
+## Modules API enhancements
+
+Redis 8.6 extends the modules API with new key metadata capabilities:
+
+- **RM_CreateKeyMetaClass**: Define new key-metadata classes for custom data organization.
+- **RM_ReleaseKeyMetaClass**: Release key-metadata classes when no longer needed.
+- **RM_SetKeyMeta**: Attach or update metadata values for keys under specific metadata classes.
+- **RM_GetKeyMeta**: Retrieve metadata values for keys under specific metadata classes.
+
+These APIs enable module developers to associate custom metadata with Redis keys, opening new possibilities for advanced data management and analytics.
+
+## Component versions
+
+Redis 8.6 continues the unified distribution approach, delivering all functionality in a single Redis Open Source package without separate modules. This includes:
+
+- **RedisTimeSeries**: Enhanced with NaN value support and new aggregation functions.
+- **RedisBloom**: Improved security with RDB loading fixes and atomic slot migration support.
+- **RedisJSON**: Better privacy protection and enhanced atomic slot migration capabilities.
+
+## Known limitations
+
+When using Redis 8.6, be aware of this current limitation:
+
+- **Redis Query Engine**: During load rebalancing operations (such as Atomic Slot Migration), cursors may miss some results due to data movement between nodes.
+
+## Component versions
+
+Redis 8.6 continues the unified distribution approach, delivering all functionality in a single Redis Open Source package without separate modules.
+
+- [Redis 8.6]({{< relref "/operate/oss_and_stack/stack-with-enterprise/release-notes/redisce/redisos-8.6-release-notes" >}})

content/develop/whats-new/redis-feature-sets.md

@@ -17,6 +17,7 @@ To use a new feature introduced in a later feature set, you must upgrade the cor
 
 | Redis feature set | What's new |
 |-------------------|------------|
+| **Feature set version:** 8.6| See [here]({{< relref "/develop/whats-new/8-6" >}})|
 | **Feature set version:** 8.4| See [here]({{< relref "/develop/whats-new/8-4" >}})|
 | **Feature set version:** 8.2| See [here]({{< relref "/develop/whats-new/8-2" >}})|
 | **Feature set version:** 8.0| See [here]({{< relref "/develop/whats-new/8-0" >}})|