Architecture

PostGamma treats an unmodified PostgreSQL source tree as compiler input. A Clang AST transformation virtualizes PostgreSQL process-local state, and a private C runtime supplies instance, role, session, signal, wait, path, and execution ownership. The generated kernel is linked behind a stable public ABI.

Host application
    │
    ├── Python API or pgm_* C ABI
    │
    ├── postgamma lifecycle, executor, and memory transport
    │
    └── AST-generated PostgreSQL 19 kernel
            ├── SQL and catalogs
            ├── planner and executor
            ├── WAL and recovery
            └── reviewed bundled extensions

No server protocol endpoint

Frontend protocol semantics are preserved through a bounded in-memory transport. Private libpq code implements PostgreSQL simple and extended protocol behavior without creating an operating-system socket. The public API does not expose libpq or PostgreSQL types.

Threaded roles, pooled sessions

Long-lived PostgreSQL roles execute as host-safe threads rather than child processes. Logical client sessions are scheduled onto a bounded set of carrier workers. A session re-enters PostgreSQL at a request boundary; it does not move a live C stack between workers.

Session state, role state, and instance state have separate generated ownership stores. This is what permits concurrent connections and multiple independent instances without turning every PostgreSQL global into one process-wide value.

Stable boundary

The host-facing ABI uses opaque handles, fixed-width scalar types, explicit structure sizes, capability negotiation, and caller-owned diagnostics. It does not include PostgreSQL headers. The Python binding consumes only this ABI and does not reach into PostgreSQL implementation symbols.

Upgrades

PostgreSQL-specific source identities and integration seams live in versioned manifests. Upgrade audits compare a candidate upstream tree without changing the supported product version. PostgreSQL 19 is the only current product contract; candidate-major results measure adaptation work rather than support.