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

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.

## Representative Queries
- Migrate Google Cloud SQL for PostgreSQL: Multi-tenant relational data
- Where can I host Multi-tenant relational data?
- I need a component-scoped export/import or reconfiguration procedure for Multi-tenant relational data, with compatibility checks, verification and rollback.

## Workflow Steps
1. **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.
2. **Source step 1**  
   Take a logical backup with `pg_dump -Fc` through the Cloud SQL Auth Proxy or an authorized network.
3. **Source step 2**  
   Check the engine major version, extensions and flags the app depends on.
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.  
   Command: `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 with the user's go-ahead, take the final dump, restore, validate, redeploy with the managed DATABASE_URL, keep Cloud SQL 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.

## 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.

## 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.

## Cost Estimate
- Currency: USD  
- Monthly Amount: 10.0  
- Note: Destination always-on monthly price of the tested sizes; apps auto-pause when idle. Source costs are unknown to Ample.