### Migrate Neon database: Transactional workflows

Move PostgreSQL data from Neon database 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` from the primary branch. Not migrated automatically: Neon branching, autoscaling and scale-to-zero semantics have no equivalent; the managed database is one instance per app.

**Cutover:** Freeze writes at the source with the user's go-ahead, take the final dump, restore, validate, redeploy the app with the managed DATABASE_URL, keep the Neon project until confirmed.

**Rollback:** keep the source untouched until you confirm; nothing at the source is changed or deleted by this guide.

### Representative Queries
- Migrate Neon database: Transactional workflows
- Where can I host Transactional workflows?
- I need a component-scoped export/import or reconfiguration procedure for Transactional workflows, with compatibility checks, verification and rollback.

### Resource Requirements
- **Primitive:** Postgres

### Infrastructure Requirements
- **Postgres:** Managed PostgreSQL 16 runs in its own microVM and is auto-provisioned when an app needs a database and no DATABASE_URL is supplied.

### Workflow Steps
1. **Inventory the source**  
   List what Neon database provides beyond the component you are moving. Out of scope here: Neon branching, autoscaling and scale-to-zero semantics have no equivalent; the managed database is one instance per app.

2. **Source step 1**  
   Take a logical backup with `pg_dump -Fc` from the primary branch.

3. **Source step 2**  
   Check the Postgres major version and extensions in use against the managed engine (PostgreSQL 16).

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 <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 at the source with the user's go-ahead, take the final dump, restore, validate, redeploy the app with the managed DATABASE_URL, keep the Neon project 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.

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

### Success Checks
- **Destination app responds on its public URL**  
  - Kind: `http_get`  
  - Path: `/`  
  - Expect: ample canary express patterns

- **Transactional-workflows check from the destination example**  
  - Kind: `http_get`  
  - Path: `/p/transactional-workflows`  
  - Expect: see the pattern fixture checks

- **Data or object counts and checksums match the source**  
  - Kind: `manual`  
  - Expect: operator comparison before cutover.

### Limitations
- Documentation only: nothing is executed automatically and no execution binding is offered.
- No full source-product parity is claimed: Neon branching, autoscaling and scale-to-zero semantics have no equivalent; the managed database is one instance per app.

### Cost Estimate
- **Currency:** USD  
- **Monthly Amount:** 10.0  
- **Components:**  
  - App server: size `s-1vcpu-1gb`, quantity 1.0, monthly amount 5.0  
  - Managed PostgreSQL database: size `s-1vcpu-1gb`, quantity 1.0, monthly amount 5.0

### Evidence Summary
- **Destination side verified:**  
  The Express pattern fixture deployed on Ample and its checks passed.

### Next Actions
- **Browse the catalog index**  
- **Search published recipes by intent, stack and constraints**  
- **Prepare a side-effect-free deployment plan for an authorized project**  
- **Read the existing agent authentication setup**  
- **Browse Neon database**  
- **Browse Transactional workflows**  
- **Browse Migrate Postgres**