## The short version

Move PostgreSQL data from Self-managed PostgreSQL to Ample, one component at a time. Destination verified on Ample: an optimistic version check and an event row written in the same transaction, a stale update rejected, and a history query over the application-owned events (history=2 conflict=rejected). Source procedure: Take a logical backup with `pg_dump -Fc` as a role that can read all application objects. Not migrated automatically: Custom extensions, tablespaces, replication topology, superuser-only settings and OS-level backups have no equivalent on the managed database. Cutover: Freeze writes with the user's go-ahead, take the final dump, restore, validate, redeploy with the managed DATABASE_URL, keep the source server until confirmed. Rollback: keep the source untouched until you confirm; nothing at the source is changed or deleted by this guide.

## What it needs

- [Postgres](/content/discover/primitive/postgres/index.html): verified (Managed PostgreSQL 16 runs in its own microVM and is auto-provisioned when an app needs a database and no DATABASE_URL is supplied.)

## Before you start

- Authorized access to the Self-managed PostgreSQL source and its export tooling  
- An inventory of every component in scope and out of scope  
- A validated backup or copy before any cutover  
- An Ample account token with servers:write, databases:read

## How to do it

1. **Inventory the source**  
   List what Self-managed PostgreSQL provides beyond the component you are moving. Out of scope here: Custom extensions, tablespaces, replication topology, superuser-only settings and OS-level backups have no equivalent on the managed database.

2. **Source step 1**  
   Take a logical backup with `pg_dump -Fc` as a role that can read all application objects

3. **Source step 2**  
   Check the major version, installed extensions, tablespaces and custom roles against the managed engine (PostgreSQL 16, no custom extensions verified)

4. **Source step 3**  
   Restore into a scratch managed database first and compare row counts

5. **Provision and restore**  
   Deploy the app once so a managed PostgreSQL 16 database exists (or create one with `ample database create --engine postgres`), then restore the dump with `pg_restore` using its connection string; keep migrations idempotent.
   
   ```
   ample database create --name <db-name> --engine postgres
   ```

6. **Validate before cutover**  
   Run the app's own checks and, for data, compare counts and checksums; the example checks are the pattern self-tests (/p/transactional-workflows).

7. **Cut over**  
   Freeze writes with the user's go-ahead, take the final dump, restore, validate, redeploy with the managed DATABASE_URL, keep the source server until confirmed.

8. **Rollback**  
   Point DNS or configuration back to the source. The source was never modified; deletion is a separate, user-executed step after validation.

## Tested examples

- **Express pattern fixture (destination)** (`tests/deploy-canaries/express-patterns`): Verified destination basis: transactional workflows.

## How to know it worked

- destination app responds on its public URL (`/` on the live URL, expect ample canary express patterns)  
- transactional-workflows check from the destination example (`/p/transactional-workflows` on the live URL, expect see the pattern fixture checks)  
- data or object counts and checksums match the source

## Cost estimate

Estimated 10.00 USD per month (size prices from pricing.toml at build revision ca0b484a7a9957c573a88d3a32dc603c3c10135a).

- app server x1 `s-1vcpu-1gb`: 5.00 USD  
- managed PostgreSQL database x1 `s-1vcpu-1gb`: 5.00 USD

Upper-bound monthly price of the tested sizes at the destination. Source costs are unknown to Ample.

## Verification evidence

- canary_run on 2026-09-21T02:34:39Z at revision `1d28ae0 (CLI 0.1.21)`: Destination side verified: the Express pattern fixture deployed on Ample (npm install, npm run build --if-present, npm run start on the node-22 template) and its checks passed (an optimistic version check and an event row written in the same transaction, a stale update rejected, and a history query over the application-owned events (history=2 conflict=rejected)). The source-side export from Self-managed PostgreSQL is documented from the vendor's standard tooling and was not executed by this catalog's evidence. (expires 2027-03-20T02:34:39Z)

## Execution binding

No execution binding. This recipe is documentation only; nothing is executed automatically.