pg-wire

Pure-Haskell driver for the PostgreSQL v3 wire protocol. No libpq, no C dependencies.

What you get

• Connection setup: TCP and Unix sockets, TLS 1.2/1.3, MD5 and SCRAM-SHA-256 auth, multi-host failover (target_session_attrs, load_balance_hosts), startup parameters.
• Connection pool: idle reaping, health checks, jittered max-life, queue mode (LIFO/FIFO), recycling modes (always/on-error), lifecycle hooks, nothunks invariants.
• Wire frames: extended query (parse / bind / describe / execute), simple query, COPY in/out, large objects, LISTEN/NOTIFY, query cancellation.
• Binary format type classes: PgEncode, PgDecode, OID metadata. Codecs for individual types live in the valiant runtime library.
• Errors: 8 structured error constructors (ConnectionError, AuthError, ProtocolError, QueryError, DecodeError, PoolTimeout, PoolClosed, ConnectionDead).

When to use this directly

pg-wire is the transport layer. Most users want the higher-level valiant runtime, which re-exports everything from pg-wire and adds compile-time SQL safety via the valiant-plugin GHC source plugin.

Use pg-wire directly only when you want raw wire-protocol access without the compile-time validation layer (e.g. for building a different ORM or for testing the protocol itself).

Installation

cabal install pg-wire

Documentation

• Top-level README: the project overview and how the four packages fit together.
• docs/: tutorial, performance notes, async architecture, gap analysis.
• docs/benchmark-results/: archived comparative numbers.

License

BSD-3-Clause. See LICENSE.