GitHub - JagritGumber/evolvsql: BEAM + Rust PostgreSQL-compatible database. Lightweight, no vacuum, infinite connections.

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This project is in early development and highly unstable. APIs, storage format, and wire protocol behavior will change without notice. Do not use in production. Contributions and feedback welcome — just know that everything is actively being reworked.

PostgreSQL-compatible database built on BEAM + Rust.

Same SQL. Same drivers. 100x less memory per connection.

Why

PostgreSQL forks an OS process for every connection — 14.6 MB each, even idle. 50 idle connections cost 729 MB. This architecture hasn't changed since 1986.

EvolvSQL replaces the process-per-connection model with BEAM lightweight processes (~2 KB active, 0 KB hibernated) and a Rust query engine for parsing and execution.

PostgreSQL 17 EvolvSQL
Per idle connection 14.6 MB 0 KB (hibernated)
Per active connection 14.6 MB ~15 KB
50 connections overhead +729 MB +768 KB
Connection model fork() per conn BEAM process
MVCC Dead tuples + VACUUM Undo-log (planned)
Cold start 0 ms 0 ms

Architecture

Client (psql, any PG driver)
  → BEAM process (2 KB per connection, supervised)
    → Rust NIF (parse + execute via pg_query)
      → Shared storage (RwLock, no per-connection duplication)

BEAM handles connections, wire protocol, fault tolerance, and clustering. Rust handles SQL parsing (via pg_query — same parser PostgreSQL uses), expression evaluation, JOINs, and storage.

What Works

  • Wire Protocol v3 — psql connects without changes
  • SQL — JOINs (INNER, LEFT, RIGHT, FULL, CROSS), subqueries (IN, EXISTS, scalar, derived), aggregates (COUNT, SUM, AVG, MIN, MAX), GROUP BY, HAVING, ORDER BY, LIMIT, OFFSET
  • DML — INSERT, UPDATE, DELETE with RETURNING
  • DDL — CREATE TABLE, DROP TABLE, SERIAL, DEFAULT, constraints (PK, UNIQUE, NOT NULL)
  • Types — int2/4/8, float4/8, numeric, bool, text, varchar, bytea, serial, vector(N)
  • Vector — vector(N) type with <-> (L2), <=> (cosine), <#> (inner product) operators — pgvector wire-compatible
  • Protocol — Simple query, extended query, prepared statements
  • Connection — Hibernation (0 KB idle), built-in pooling via BEAM
  • Tests — 97 engine tests passing

Quick Start

# Clone
git clone https://github.com/JagritGumber/evolvsql.git
cd evolvsql

# Dependencies: Elixir ~1.18, OTP 27, Rust (2024 edition)
mix deps.get

# Build the Rust NIF
cd native/engine && cargo build --release && cd ../..

# Start EvolvSQL
mix run --no-halt

# Connect with psql (default port 5432)
psql -h localhost -p 5432 -U postgres

Roadmap

Phase Status What
Wire protocol + basic CRUD Done psql connects, INSERT/SELECT/UPDATE/DELETE
JOINs + aggregates Done All JOIN types, GROUP BY, HAVING, ORDER BY
Subqueries Done IN, EXISTS, scalar, derived tables
Connection hibernation Done 0 KB idle connections
Vector type (pgvector compat) Done vector(N), distance operators
Persistent storage Next B-tree indexes, WAL, crash recovery
ACID transactions Planned BEGIN/COMMIT/ROLLBACK, isolation levels
Undo-log MVCC Planned Zero bloat, no VACUUM
BEAM clustering Planned Multi-node distribution

See FEATURES.md for the complete specification.

Benchmarks

Memory: 50 idle connections

PostgreSQL 17 EvolvSQL
Additional memory +729 MB +0 KB
Per connection 14.6 MB 0 KB (hibernated)

Query throughput

EvolvSQL achieves 2x the query throughput of PostgreSQL on equivalent hardware in initial benchmarks.

License

Business Source License 1.1 — the same license used by CockroachDB.

  • Use EvolvSQL for anything, including commercial production use
  • Self-host freely
  • Cannot offer EvolvSQL as a managed database service

Converts to AGPL-3.0 five years after each version's release.

Links