Migrate Heroku Postgres: JSON document metadata

Summary

Move PostgreSQL data from Heroku Postgres to Ample, one component at a time. Destination verified on Ample: a jsonb column with a GIN index queried by path and containment, with an aggregate over matching documents (json=ok). Source procedure: Take a logical backup with heroku pg:backups:capture and download it, or pg_dump -Fc against the credentials from heroku pg:credentials:url. Not migrated automatically: Heroku Postgres followers, forks, rollback (PITR) and dataclips have no equivalent on the managed database. Cutover: Put the app in maintenance mode with the user's go-ahead, take the final backup, restore, validate, redeploy with the managed DATABASE_URL, keep the Heroku database until confirmed. Rollback: keep the source untouched until you confirm; nothing at the source is changed or deleted by this guide.

Infrastructure requirements

• Postgres: 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.)

Prerequisites

• Authorized access to the Heroku Postgres 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

Exact tested configuration

• template: node-22
• runtime: node
• size: s-1vcpu-1gb
• install: npm install
• build: npm run build --if-present
• start: npm run start

Steps

1. Inventory the source. List what Heroku Postgres provides beyond the component you are moving. Out of scope here: Heroku Postgres followers, forks, rollback (PITR) and dataclips have no equivalent on the managed database.
2. Source step 1. Take a logical backup with heroku pg:backups:capture and download it, or pg_dump -Fc against the credentials from heroku pg:credentials:url
3. Source step 2. Check the Postgres major version and extensions 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 <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/json-document-metadata).
7. Cut over. Put the app in maintenance mode with the user's go-ahead, take the final backup, restore, validate, redeploy with the managed DATABASE_URL, keep the Heroku database 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: JSON document metadata.

Success checks

• destination app responds on its public URL (/ on the live URL, expect ample canary express patterns)
• json-document-metadata check from the destination example (/p/json-document-metadata on the live URL, expect see the pattern fixture checks)
• 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 Heroku Postgres'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: Heroku Postgres followers, forks, rollback (PITR) and dataclips have no equivalent on the managed database.
• 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.

Cost estimate

Estimated 10.00 USD per month (size prices from pricing.toml at build revision a1b8c38919e59cd035ebabaced73cf84ece24371).

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

Destination always-on monthly price of the tested sizes; apps auto-pause when idle. Source costs are unknown to Ample.

Verification evidence

• canary_run on 2026-09-21T02:34:39Z at revision 1d28ae0-dirty (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 (a jsonb column with a GIN index queried by path and containment, with an aggregate over matching documents (json=ok)). The source-side export from Heroku Postgres 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.