Feature Status Alignment

Document: Feature implementation status vs documentation claims Version: v3.4.0 Updated: 2025-12-25

---

Purpose

This document provides an honest assessment of feature implementation status, aligning marketing claims in the README with actual code implementation. It serves as a reference for developers and users to understand what is fully implemented vs. work-in-progress.

---

Feature Status Matrix

Core Database Features

Feature	README Claim	Implementation Status	Notes
PostgreSQL Compatibility	95%+ PostgreSQL 17	Partial	Custom wire protocol, most SQL syntax supported
Embedded Mode	SQLite-style	Implemented	EmbeddedDatabase API
Server Mode	PostgreSQL-style	Implemented	TCP server with PG wire protocol
In-Memory Mode	ACID-compliant	Implemented	Full transaction support
Built-in Encryption	AES-256-GCM	Implemented	TDE with <3% overhead
ACID Transactions	MVCC snapshot isolation	Implemented	Full MVCC support

v3.x Advanced Features

Feature	README Claim	Implementation Status	Notes
Product Quantization	8-16x compression	Implemented	src/vector/quantization/
Database Branching	Git-like workflows	Implemented	CREATE/DROP/MERGE BRANCH
Time-Travel Queries	AS OF TIMESTAMP	Implemented	src/storage/time_travel.rs
Materialized Views	Auto-refresh, ALTER SET, REFRESH INCREMENTALLY	Implemented	CPU-aware scheduling, delta tracking
Vector Search	HNSW with PQ	Implemented	src/vector/
RETURNING Clause	INSERT/UPDATE/DELETE	Implemented	Full projection support
json_agg() Function	PostgreSQL compatible	Implemented	Phase 1.10 (v3.4.0)
Array Subscript	1-based indexing	Implemented	Phase 2 (v3.4.0)
Array Concatenation			operator

Multi-Tenancy Features (v3.2+)

Feature	README Claim	Implementation Status	Notes
Row-Level Security	Policy-based	Implemented	src/tenant/
Tenant Quotas	Connection/Storage/QPS	Implemented	src/multi_tenant/quotas.rs
Change Data Capture	Enterprise-grade	Partial	Core CDC, persistence pending
Multi-User Sessions	Independent contexts	Implemented	Session isolation

Sync/Replication Features

Feature	README Claim	Implementation Status	Notes
Conflict Detection	-	Implemented	Vector clock comparison
Vector Clocks	-	Implemented	src/sync/delta_applicator.rs
Field-Level Merge	-	Implemented	JSON merge with server precedence
Change Log Query	-	Implemented	get_changes_since()
Distributed Sync	-	Not Implemented	Future roadmap item

Compute Engine

Feature	README Claim	Implementation Status	Notes
Volcano Executor	Query execution	Implemented	8 executor types
Aggregations	Standard SQL	Implemented	COUNT, SUM, AVG, MIN, MAX, STDDEV, VARIANCE
Trigger WHEN	Conditions	Implemented	evaluate_when_condition()
EXPLAIN Diff	Plan comparison	Implemented	Tree and config diff

---

Claims Requiring Caveats

"95%+ PostgreSQL 17 Compatibility"

Actual Status: Significant PostgreSQL syntax and wire protocol support, but: - Uses custom wire protocol implementation (not pgwire crate) - Some advanced features may differ from PostgreSQL behavior - Tested primarily with basic SQL operations

Recommendation: Consider rephrasing to "PostgreSQL-compatible SQL syntax and wire protocol"

"Panic-Free Production Code"

Actual Status: Production code paths use proper error handling: - All 27 TODO/FIXME items resolved - 58 unwrap() patterns reviewed and addressed - parking_lot::RwLock (no poison risk) - once_cell::Lazy for regex patterns - panic! calls exist only in test code

Verification: Only test code contains panic! macro (47 occurrences in #[test] functions)

"GA Status"

Actual Status: Core features are implemented and tested: - All critical security items resolved (Argon2id password hashing) - Core SQL features complete - Sync module has core features but "experimental" flag

Consideration: README badge shows "GA" but Cargo.toml has "sync-experimental" feature

---

Recent Additions (v3.4.0)

Phase 1.10: JSON Aggregation

• [x] json_agg() aggregate function with ORDER BY support
• [x] Integration with materialized views
• [x] PostgreSQL-compatible NULL handling
• [x] Type safety and JSONB output
• [x] Comprehensive documentation: PHASE_1_10_JSON_AGGREGATION.md

Phase 2: Array Operations

• [x] Array subscript operator with 1-based indexing
• [x] Array concatenation with || operator
• [x] Type coercion and promotion rules
• [x] NULL-safe operations
• [x] Multi-dimensional array support
• [x] Comprehensive documentation: PHASE_2_ARRAY_OPERATIONS.md

Phase 3: Type Verification

• [x] UUID type validation
• [x] Boolean type verification
• [x] BYTEA type support
• [x] Enhanced type safety across operations

Phase 3.x: Materialized Views Enhancements

• [x] ALTER MATERIALIZED VIEW SET for post-creation configuration
• [x] REFRESH MATERIALIZED VIEW INCREMENTALLY explicit keyword
• [x] AutoRefreshWorker CPU-aware scheduling integration
• [x] Priority-based MV refresh queue
• [x] Delta tracking cleanup after refresh
• [x] Integration tests for all new MV features

---

Resolved Issues (2025-12-16)

The following issues from the Gemini analysis have been resolved:

Security

• [x] Password hashing with Argon2id
• [x] unwrap() patterns in production code

Core SQL

• [x] RETURNING clause for INSERT/UPDATE/DELETE
• [x] Volcano-model query execution
• [x] Standard aggregation functions
• [x] Trigger WHEN condition evaluation

Sync/Replication

• [x] Change log query mechanism
• [x] Conflict detection with vector clocks
• [x] Field-level JSON merge

Storage

• [x] Histogram-based selectivity estimation
• [x] Key parsing for dirty tracking
• [x] Materialized view refresh history

API

• [x] Row count tracking
• [x] Total count in responses
• [x] OpenAPI routes enabled
• [x] SSE streaming for chat completions

---

Remaining Work

Short-Term (Documentation)

1. Update README PostgreSQL compatibility claim wording
2. Clarify sync module status in feature table
3. Add "implementation status" column to feature comparison

Medium-Term (Code)

1. CDC persistence layer
2. Distributed sync coordinator
3. RETURNING tuple capture optimization

Long-Term (Architecture)

1. Consider pgwire crate adoption for protocol
2. Multi-crate architecture evaluation
3. Cloud integration tools

---

References

• Master Checklist - Implementation tracking
• TODO/FIXME Findings - All resolved
• unwrap() Findings - All addressed
• Archive Analysis - Historical context

---

Version 3.4.0 Summary

v3.4.0 completes Phases 1.10-3.x of the development roadmap:

1. Phase 1.10 (JSON Aggregation): Full PostgreSQL-compatible json_agg() function
2. Phase 2 (Array Operations): Subscript and concatenation operators
3. Phase 3 (Type Verification): Enhanced type system with UUID, Boolean, BYTEA
4. Phase 3.x (Materialized Views): ALTER MV SET, REFRESH INCREMENTALLY, AutoRefreshWorker

All features are production-ready with comprehensive testing and documentation.

---

Last Updated: 2025-12-25