Prisma

Prisma is a TypeScript/JavaScript ORM with a read replicas extension.

Read replica routing

Use the @prisma/extension-read-replicas extension. Point both the primary and replica at halephant with different users:

db.ts

import { PrismaClient } from "@prisma/client";
import { readReplicas } from "@prisma/extension-read-replicas";

const prisma = new PrismaClient({
    datasourceUrl: "postgresql://myapp:password@halephant:6432/myapp",
}).$extends(
    readReplicas({
        url: "postgresql://myapp_ro:password@halephant:6432/myapp",
    }),
);

Prisma sends read operations (findMany, findFirst, findUnique, count, aggregate, groupBy) to the replica URL. All write operations and $transaction go to the primary URL.

Prisma doesn't send BEGIN READ ONLY. The separate user approach lets halephant handle routing. See the read replica guide for halephant configuration.