Crate mempill_postgres 

mempill-postgres

PostgreSQL-backed PersistencePort adapter for mempill.

Usage

use mempill_postgres::{open_postgres, PostgresEngine};
use mempill_core::{EngineConfig, NoOpOracle, NoOpVector};
use std::sync::Arc;

let conn_str = "host=localhost port=5432 user=mempill dbname=mempill password=secret";
let engine: PostgresEngine<NoOpOracle, NoOpVector> = open_postgres(conn_str, None, None, EngineConfig::default())?;

Topology-b vs topology-a

One backend per deployment: downstream consumers depend on EITHER mempill-sqlite OR mempill-postgres, never both.

Concurrency model

• r2d2 pool (max 20 connections) enables concurrent cross-agent transactions.
• pg_advisory_xact_lock(hashtext(agent_id)::bigint) serializes same-agent writes at the DB level.
• UNIQUE(agent_id, stream_seq) on ledger_entries provides OCC belt-and-suspenders against duplicate sequence numbers.
• requires_global_write_serialization() returns false — EngineHandle skips the global write lock, enabling true Postgres concurrency across agents.

Modules

migrations

Structs

PostgresPendingStore

PostgreSQL-backed PendingAdjudicationPort implementation.

PostgresPersistenceStore

The PostgreSQL-backed PersistencePort implementation.

PostgresTxn

An open, uncommitted Postgres transaction scoped to one agent_id.

Enums

PostgresStoreError

Error type for PostgresPersistenceStore operations.

Functions

open_postgres

Convenience constructor: build a PostgresEngine<O, V> (an EngineHandle backed by PostgresPersistenceStore) from a connection string.

open_postgres_with_oracle

Convenience constructor: build a PostgresEngine<O, V> wired with a real oracle and the Postgres-backed pending-adjudication store.

Type Aliases

PostgresEngine

Type alias for an EngineHandle backed by PostgresPersistenceStore.