All notable changes to minikv will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

• No unreleased entries yet.

• Notebook-first Python SDK with analytics-oriented client helpers
• End-to-end quickstart example for vector search and time-series workflows
• Dataframe conversion helpers for pandas, polars, and pyarrow

• New vector endpoints:
  • POST /vector/upsert
  • POST /vector/query
  • GET /admin/vector/stats
• Cosine similarity top-k matching
• Persistent on-disk vector index snapshot (coord-data/vector_index.json)

• Production handlers for POST /ts/write and POST/GET /ts/query
• Automatic initialization of the time-series engine
• Query support for tags, aggregation, resolution, and limits
• Admin time-series stats endpoint now backed by live engine stats

• Helm chart added with dev/staging/prod values profiles
• Observability bundle:
  • Grafana dashboard provisioning and default minikv overview dashboard
  • Prometheus alert rules for availability and latency/error SLOs
• Backup/restore runbook for release and disaster-recovery drills
• GA preflight release script and Makefile targets for release validation

• README restructured for GA usage and operations
• CONTRIBUTING guide updated for v1 release workflow
• Release engineering runbook added for reproducible v1.0.0 process

• Updated shell automation scripts to use Kubernetes-aligned health probes (/health/live)

• Custom Resource Definition (CRD) for MiniKVCluster
• Automated deployment and scaling of coordinator and volume nodes
• RBAC configuration with proper permissions
• StatefulSet management for persistent storage
• ConfigMap generation from cluster spec
• Horizontal Pod Autoscaler (HPA) support
• ServiceMonitor for Prometheus integration
• Example manifests for basic and production clusters

• Dedicated TimeseriesEngine for time-series workloads
• Multiple resolution levels (raw, 1min, 5min, 1hour, 1day)
• Automatic downsampling with configurable retention
• Aggregation functions: sum, avg, min, max, count, first, last, stddev
• Delta and gorilla compression for efficient storage
• Time-range queries with aggregation support

• Geographic data locality for compliance (GDPR, data residency)
• Multiple routing strategies:
  • Nearest region (latency-based)
  • Primary region (consistency-based)
  • Round-robin (load distribution)
  • Geo-fenced (compliance-based)
• Haversine distance calculation for region selection
• Per-key prefix region assignment
• Region health monitoring with automatic failover
• Geo-fencing rules for data sovereignty

• Automatic data movement between storage tiers
• Tier levels: Hot, Warm, Cold, Archive
• Policy-based tiering rules:
  • Access frequency (access count in time window)
  • Data age (time since creation)
  • Value size (bytes)
  • Last access time (idle duration)
• Access pattern tracking with history
• Compression per tier (none, lz4, zstd, snappy, gzip)
• S3-compatible archive tier support
• Statistics and reporting for tier distribution

• Zero-copy I/O operations using Linux io_uring
• Batched submissions for reduced syscalls
• Configurable submission/completion queue depths
• Optional kernel polling (SQPOLL) for ultra-low latency
• Registered buffers for zero-copy transfers
• Direct I/O bypass of page cache
• Graceful fallback to standard I/O on unsupported systems
• Write batching for small operations

• k8s_operator.rs - Kubernetes controller and CRD types
• timeseries.rs - Time-series storage engine
• geo.rs - Geo-partitioning router
• tiering.rs - Data tiering manager
• io_uring.rs - io_uring I/O backend

• k8s/crds/minikvcluster.yaml - CRD definition
• k8s/rbac/operator-rbac.yaml - Operator permissions
• k8s/operator/deployment.yaml - Operator deployment
• k8s/examples/basic-cluster.yaml - Minimal cluster example
• k8s/examples/production-cluster.yaml - Production-ready example

• Asynchronous replication to remote datacenters
• Multiple conflict resolution strategies:
  • Last-Write-Wins (timestamp-based)
  • Vector Clocks (causality tracking)
  • Local-First (prefer local DC writes)
  • Primary-First (prefer primary DC writes)
• DC-aware routing for read/write operations
• Configurable replication lag monitoring and alerts
• Per-datacenter replication status tracking

• Real-time capture of all data changes (INSERT, UPDATE, DELETE)
• Configurable sinks for event delivery:
  • Webhook sink (HTTP POST to external endpoints)
  • Kafka sink (for event streaming platforms)
  • File sink (for local debugging/archival)
  • Memory sink (for testing)
• Event filtering by operation type and key prefix
• Sequence numbers for guaranteed ordering
• Old value capture for UPDATE and DELETE operations

• Embedded web dashboard for cluster monitoring
• Real-time cluster status visualization
• API key management interface
• Backup/restore controls with progress tracking
• Plugin management UI
• Cross-DC replication status monitoring
• Responsive dark theme design

• Full backup support (complete snapshot)
• Incremental backup support (changes since last backup)
• Backup compression (configurable)
• Backup encryption support
• Multiple backup destinations:
  • Local filesystem
  • S3-compatible storage
• Point-in-time recovery
• Checksum verification during restore
• Backup manifest with metadata

• Extensible plugin architecture
• Plugin types:
  • Storage plugins (custom backends)
  • Auth plugins (custom authentication)
  • Hook plugins (event listeners)
  • Middleware plugins (request interceptors)
• Plugin lifecycle management (load, enable, disable, unload)
• Plugin dependencies and version compatibility
• Built-in logging hook plugin example

• GET /admin/ui - Admin web dashboard
• POST /admin/backup - Create a new backup
• GET /admin/backups - List all backups
• GET /admin/backups/:id - Get backup details
• DELETE /admin/backups/:id - Delete a backup
• POST /admin/restore - Restore from backup
• GET /admin/replication/status - Replication status
• GET /admin/plugins - List plugins
• POST /admin/plugins/:id/enable - Enable a plugin
• POST /admin/plugins/:id/disable - Disable a plugin
• GET /admin/cdc/status - CDC status

• Added async-trait for async plugin traits
• New modules: replication, cdc, backup, plugin, admin_ui
• Comprehensive unit tests for all new features
• Vector clock implementation for distributed causality

• POST /admin/import - Batch import key-value pairs from JSON payload
• GET /admin/export - Streaming export of all key-value pairs as NDJSON

• POST /transaction - Execute multiple operations (put/delete) in a single request
• Returns detailed results for each operation with success/error status

• GET /search?value=<substring> - Search for keys whose values contain the specified substring

• S3-compatible API now supports pluggable persistent storage backends (RocksDB, Sled)
• Objects can be stored durably by configuring storage backend in config.toml

• API Key Authentication - Secure access control with API keys
  • Generate and manage API keys via admin endpoints
  • Keys are securely hashed using Argon2id
  • Support for key expiration and revocation
  • Headers: Authorization: Bearer <api_key> or X-API-Key: <key>
• JWT Token Support - Stateless authentication tokens
  • Generate JWT tokens from valid API keys
  • Configurable token expiration (default: 24 hours)
  • HMAC-SHA256 signature verification
• Role-Based Access Control (RBAC) - Fine-grained permissions
  • Three role levels: Admin, ReadWrite, ReadOnly
  • Middleware enforcement on all protected routes
  • Role-based endpoint restrictions
• Multi-tenancy - Tenant isolation for data
  • Tenant identifier attached to each API key
  • S3 objects tagged with tenant ownership
  • Tenant extraction from authenticated requests
• Encryption at Rest - AES-256-GCM data encryption
  • HKDF-SHA256 key derivation from master key
  • Per-object random nonces for security
  • Separate keys for data and WAL encryption
  • Transparent encryption/decryption with backward compatibility
• Tenant Quotas - Resource limits per tenant
  • Storage limits (bytes)
  • Object count limits
  • Request rate limiting per tenant
  • Prometheus metrics for quota usage
• Audit Logging - Structured audit logs for all admin and sensitive actions (file + stdout)
• Persistent Storage Backends - Pluggable storage: in-memory, RocksDB, Sled (configurable via config.toml)
• Watch/Subscribe System - Real-time key change notifications (WebSocket & SSE endpoints, production-ready)
  • Subscribe to key changes via /watch/sse (SSE) or /watch/ws (WebSocket)
  • Events: PUT, DELETE, REVOKE (with key, tenant, timestamp)
  • Integrated with all S3/data and admin modification endpoints

• POST /admin/keys - Create new API key
• GET /admin/keys - List all API keys
• GET /admin/keys/:id - Get specific API key details
• POST /admin/keys/:id/revoke - Revoke an API key
• DELETE /admin/keys/:id - Delete an API key
• GET /admin/audit - Download or stream audit logs (NEW)
• GET /admin/subscribe - Subscribe to key change events (NEW, preview)

• Constant-time password verification with Argon2
• Secure key generation using cryptographic RNG
• Authentication middleware for route protection
• Request validation and tenant context propagation
• Audit log hooks in all admin and data modification endpoints

• Pluggable backend: select in-memory, RocksDB, or Sled via config
• S3/data endpoints refactored to use trait abstraction
• Persistent storage for all S3/data paths when enabled

• Audit log file and stdout output
• Prometheus metrics for audit, quota, and storage backend
• Watch/subscribe system for real-time notifications (preview)

• S3 store entries now include tenant field
• Authorization required for protected endpoints (when auth enabled)
• Storage backend must be selected in config (default: in-memory)

• TTL Support - Keys can now expire automatically with millisecond precision
  • Set TTL via X-Minikv-TTL header on PUT requests
  • Automatic cleanup of expired keys
• LZ4 Compression - Optional transparent compression for values > 1KB
  • Configurable via CompressionMode::Lz4
  • Automatic decompression on read
• Rate Limiting - Token bucket algorithm with per-IP tracking
  • Configurable requests per second and burst size
  • Returns X-RateLimit-* headers
• Kubernetes Health Probes - Production-ready health endpoints
  • /health/ready - Readiness probe (checks volumes + Raft)
  • /health/live - Liveness probe (always returns OK)
• Enhanced Metrics - Prometheus histograms and per-endpoint stats
  • Request latency histograms with configurable buckets
  • Per-endpoint request/error counters
  • TTL and rate limiting metrics
• Request Tracing - Structured logging with request IDs
  • Unique X-Request-ID header for each request
  • Correlation across distributed components

• Updated blob format to support compression metadata
• Index snapshots now include TTL expiration data (KVINDEX3 format)
• Better WAL replay with v0.5.0 format support

• Blob storage format changed (existing data will be migrated on read)
• Index snapshot format updated to KVINDEX3

• Admin dashboard endpoint (/admin/status) for live cluster state and monitoring (NEW)
  • Shows role, leader, volumes, S3 object count, and more, for monitoring and UI integration
• S3-compatible API (PUT/GET, in-memory demo) as a new object storage interface (NEW)
  • Store and retrieve objects via /s3/:bucket/:key
• Full documentation and automated tests for all new endpoints

• Better system observability: admin and metrics endpoints now cover all cluster state
• Clean separation of admin/user APIs
• Documentation expanded and migrated for new features
• Test coverage increased for dashboard and S3 features

• All v0.4.0 roadmap features implemented and tested
• Ready for integration with UIs, external metrics dashboards, and S3-demo clients
• Cluster state easily visible and integrable via admin endpoint

• Range queries (efficient scans across keys)
• Batch operations API (multi-put/get/delete)
• TLS encryption for HTTP and gRPC (production-ready security)
• Flexible configuration: file, environment variables, and CLI override
• All code, comments, and documentation now in English
• 100% green CI: build, test, lint, format

• CLI and API fully support new batch and range operations
• Example config and all templates now in English
• Refined error handling and configuration merging
• Documentation and README updated for v0.3.0

• All v0.3.0 roadmap features are implemented and production-ready
• No incomplete logic remains
• Ready for enterprise deployment and future advanced features

• Full multi-node Raft consensus: leader election, log replication, snapshots, commit index, recovery, partition detection
• Advanced Two-Phase Commit (2PC) streaming: chunked blob streaming, error propagation, retry, timeouts
• Automatic cluster rebalancing: detects overloaded/underloaded volumes, moves blobs and updates metadata
• Prometheus metrics endpoint: /metrics exposes cluster and volume stats, Raft role, replication lag, health
• Professional integration, stress, and recovery tests
• All scripts, test templates, and documentation translated/adapted to English

• All core features are implemented and production-ready
• No incomplete logic remains
• All documentation, comments, and scripts are in professional English
• Ready for enterprise deployment and further extension

• Raft consensus for coordinator high availability
• 2PC (Two-Phase Commit) for distributed writes
• Write-Ahead Log (WAL) for durability with configurable fsync
• Dynamic sharding across 256 virtual shards
• HRW (Highest Random Weight) placement for replica selection
• gRPC internal coordination protocol
• HTTP REST API for public access

• Segmented append-only log architecture
• In-memory HashMap index for O(1) lookups
• Bloom filters for fast negative lookups
• Index snapshots for 5ms restarts (vs 500ms rebuild)
• CRC32 checksums on every record
• Automatic background compaction

• RocksDB metadata store for key → replicas mapping
• Raft leader election (simplified single-node for v0.1)
• Volume health monitoring
• Placement manager with shard rebalancing
• RESTful HTTP API: PUT, GET, DELETE

• Blob storage with segmented logs
• WAL for durable writes
• gRPC service for 2PC operations
• HTTP API for direct blob access
• Automatic compaction based on threshold
• Index snapshot persistence

• Coordinator commands: serve, compact, rebalance
• Volume commands: serve, compact
• CLI: verify, repair, batch, range