durable job state.md

Migrate Amazon RDS for PostgreSQL: Durable job state

Summary

Move PostgreSQL data from Amazon RDS for PostgreSQL to Ample, one component at a time. Destination verified on Ample: a jobs table with a state and attempts counter, processing inside a row-locked transaction, and a second run that is a no-op (job=done attempts=1 idempotent=true). Source procedure: Take a logical backup with pg_dump -Fc from a network location that can reach the instance. Not migrated automatically: Multi-AZ failover, read replicas, IAM authentication, PITR and Performance Insights have no equivalent on the managed database. Cutover: Freeze writes at the source with the user's go-ahead, take the final dump, restore, validate, redeploy with the managed DATABASE_URL, keep RDS 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 Amazon RDS for 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

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

Inventory the source. List what Amazon RDS for PostgreSQL provides beyond the component you are moving. Out of scope here: Multi-AZ failover, read replicas, IAM authentication, PITR and Performance Insights have no equivalent on the managed database.
Source step 1. Take a logical backup with pg_dump -Fc from a network location that can reach the instance
Source step 2. Check the engine major version, extensions and parameter-group settings the app depends on
Source step 3. Restore into a scratch managed database first and compare row counts
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
```
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/durable-job-state).
Cut over. Freeze writes at the source with the user's go-ahead, take the final dump, restore, validate, redeploy with the managed DATABASE_URL, keep RDS until confirmed.
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: durable job state.

Success checks

destination app responds on its public URL (/ on the live URL, expect ample canary express patterns)
durable-job-state check from the destination example (/p/durable-job-state 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 Amazon RDS for PostgreSQL'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: Multi-AZ failover, read replicas, IAM authentication, PITR and Performance Insights 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 jobs table with a state and attempts counter, processing inside a row-locked transaction, and a second run that is a no-op (job=done attempts=1 idempotent=true)). The source-side export from Amazon RDS for 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.