Postgres

Source: src/Drizzle/Postgres.ts

Open a Drizzle/Postgres database from a connection URL using the drizzle-orm/effect-postgres integration.

Returns a chainable Proxy over EffectPgDatabase (via proxyChain) — every property read records a step, every call records args, and the chain is replayed against the resolved drizzle db when it’s finally yielded as an Effect. Callers don’t need a separate yield* conn step:

const db = yield* Drizzle.postgres(hd.connectionString);

fetch: Effect.gen(function* () {
  const rows = yield* db.select().from(users);
});

Behind the scenes the actual connect work is wrapped in Effect.cached, so the pool is built at most once per JS realm. Yielding the connection string is also deferred until first query, so deploy / plan-time invocations (where WorkerEnvironment isn’t provided) never trigger a real connection attempt.

The PgClient pool is built against an isolated, never-closing Scope so it outlives whatever scope this helper is yielded under. In a Cloudflare Worker the surrounding Cloudflare.Worker runs init inside Effect.scoped, which closes after returning the exports object — without an isolated scope, the pool’s end finalizer would fire there and every subsequent request would see “Cannot use a pool after end”.