Every feature Oracle sells. Under 200 megabytes.

Vault implements full ACID compliance with MVCC (Multi-Version Concurrency Control) — readers never block writers, writers never block readers. The system supports all four SQL isolation levels: READ UNCOMMITTED, READ COMMITTED, REPEATABLE READ, and SERIALIZABLE. Transaction deadlock detection resolves conflicts in microseconds. Write-ahead logging (WAL) ensures crash recovery with zero data loss. Because Rust's ownership model prevents data races at compile time, Vault's transaction engine achieves concurrency safety that C-based databases enforce at runtime — with measurably lower overhead.

Most databases force you to choose: row storage for transactions, or columnar storage for analytics. Vault does both. Tables can be configured with row-oriented storage (optimized for point queries, inserts, and updates), columnar storage (optimized for analytical scans and aggregations), or hybrid storage (hot data in rows, historical data automatically tiered to columnar). The query optimizer automatically selects the optimal access path based on the query pattern — no manual tuning required.

AI workloads require vector storage and similarity search — and in 2026, bolting on a vector extension is no longer acceptable. Vault includes native HNSW (Hierarchical Navigable Small World) vector indexes as a first-class data type. Store embeddings alongside relational data, query both with standard SQL, and build RAG pipelines, recommendation engines, and semantic search applications without a separate vector database. The vector engine supports up to 4,096-dimensional embeddings with sub-millisecond approximate nearest neighbor queries at million-scale datasets.

High availability is not an add-on — it is built into the core. Vault implements the Raft consensus protocol for automatic leader election, synchronous multi-node replication, and zero-downtime failover. When a primary node fails, a new leader is elected in under 3 seconds with zero data loss. Read replicas scale horizontally for read-heavy workloads. Cross-region replication supports disaster recovery and global distribution. The entire HA stack is included in the 187MB binary — no separate Data Guard license, no Oracle RAC, no third-party clustering software.

Enterprise security is native, not bolted on. Vault provides row-level security policies that restrict data access based on user attributes — enabling multi-tenant applications where each tenant sees only their own data through standard SQL queries. Transparent Data Encryption (TDE) encrypts data at rest with AES-256. TLS 1.3 encrypts data in transit. Complete audit logging tracks every query, every login, every schema change, every permission grant — with tamper-evident log chains. Because Vault is written in Rust, the entire database engine is immune to the buffer overflow and memory corruption vulnerabilities that generate CVEs in Oracle and PostgreSQL every year.

Oracle requires a certified DBA, a multi-day installation process, and a 12GB download. PostgreSQL requires package managers, initialization scripts, and configuration file editing. Vault requires a download and a single command. The entire database engine ships as one compiled binary with zero external dependencies. It runs on any Linux distribution, any cloud instance, any container orchestrator, any bare-metal server. Configuration is sensible by default and tunable through SQL commands — not hidden configuration files. Upgrades are a binary replacement with automatic schema migration.