multi tenant relational data.md

Migrate Google Cloud SQL for PostgreSQL: Multi-tenant relational data

Summary

Move PostgreSQL data from Google Cloud SQL for PostgreSQL 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 through the Cloud SQL Auth Proxy or an authorized network. Not migrated automatically: Cloud SQL Auth Proxy/IAM authentication, high availability and PITR 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 Cloud SQL 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 Google Cloud SQL 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 Google Cloud SQL for PostgreSQL provides beyond the component you are moving. Out of scope here: Cloud SQL Auth Proxy/IAM authentication, high availability and PITR have no equivalent on the managed database.
Source step 1. Take a logical backup with pg_dump -Fc through the Cloud SQL Auth Proxy or an authorized network
Source step 2. Check the engine major version, extensions and flags 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/multi-tenant-relational-data).
Cut over. Freeze writes with the user's go-ahead, take the final dump, restore, validate, redeploy with the managed DATABASE_URL, keep Cloud SQL 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: multi-tenant relational data.

Success checks

destination app responds on its public URL (/ on the live URL, expect ample canary express patterns)
multi-tenant-relational-data check from the destination example (/p/multi-tenant-relational-data 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 Google Cloud SQL 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: Cloud SQL Auth Proxy/IAM authentication, high availability and PITR 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

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 tenant column on every row and query, with a cross-tenant read returning nothing (tenant_isolation=ok)). The source-side export from Google Cloud SQL 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)

Last verified: 2026-09-21T02:34:39Z

Execution binding

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