# Migrate Neon Database: Multi-tenant Relational Data

## Summary
Move PostgreSQL data from Neon database to Ample, one component at a time. Destination verified on Ample: a tenant column on every row and query, with a cross-tenant read returning nothing (tenant_isolation=ok).

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.

## Prerequisites
- Authorized access to the Neon database 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

## Workload
Multi-tenant relational data

## Migration Source
Neon database

## 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.
   ```bash
   ample database create --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/multi-tenant-relational-data).

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.

## Success Checks
- Destination app responds on its public URL
- Multi-tenant-relational-data check from the destination example
- Data or object counts and checksums match the source

## Limitations
- Documentation only: nothing is executed automatically and no execution binding is offered.
- The source-side procedure is documented from Neon database's standard tooling and was not executed in this catalog's evidence; the destination side was verified with the pattern fixture.
- 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.
- Verified on the node-22 template at s-1vcpu-1gb; region, compliance, and request-duration limits are unknown.
- Managed PostgreSQL 16 only; extensions, connection limits, and backup or restore procedures on the managed side are not verified beyond the pattern checks.