gem-hunter

Egres is a Postgres-compatible database for heavy, multi-tenant workloads. Written in Zig, Egres is not a Postgres rewrite: it is a ground-up, first-principles redesign.

This README is barebones on purpose. The full documentation is at egresql.io. Also read the announcement post. If you like the project, give it a star.

curl -fsSL https://egresql.io/install.sh | sh

The installer puts the latest release's egres on your path. Release tarballs for Linux x86_64 and Apple Silicon are on the releases page, with a SHA256SUMS beside them.

A single node needs no flags: it keeps its store and write-ahead log under egres-data in the working directory and listens for Postgres clients on port 3210.

egres
psql -h localhost -p 3210 -d egres

egres --help lists every flag with its default.

Zig 0.16.0, plus bash, make and curl: the first build downloads jemalloc and compiles it with Zig's own C compiler. No gcc or clang is needed; the Postgres parser and the compression libraries are vendored and compiled by Zig too.

zig build -Doptimize=ReleaseFast
zig-out/bin/egres --help

A plain zig build is a Debug build: slow, every assertion on, and debug log lines in.

zig build test runs the unit tests; scripts/e2e.sh drives a real server over pgwire with psql; scripts/prepush.sh is the gate a push to main passes, and CI runs both on every push. The conventions the code follows are in AGENTS.md.

Jepsen tests check snapshot isolation over pgwire, including process crashes and pauses. See the SQL compatibility notes.

Most of the Egres code base was written using AI agents: Claude Opus and then Claude Fable. I drove both the architecture and code design. I reviewed every live code path myself, line by line, and iterated on it until it was correct and struck the right balance between performance and readability.

A pull request is expected to have had the same quality of human review before it is considered.

Apache License 2.0, see LICENSE. Every source file carries an SPDX header. third_party/ and the Jepsen harness (EPL-2.0) keep their own licenses.