# `mix mailglass.upgrade.v2_schema`
[🔗](https://github.com/szTheory/mailglass/blob/v2.7.0/lib/mix/tasks/mailglass.upgrade.v2_schema.ex#L1)

Generates a Route B move migration that relocates mailglass's four core tables
from `public` into a dedicated `mailglass` schema — the recommended upgrade path
for adopters running the 1.x `public` install who are moving to mailglass 2.0.

The emitted migration is metadata-only and transactional:

  * `SET LOCAL lock_timeout = '5s'` so the move fails fast (SQLSTATE `55P03`)
    rather than queueing behind a long reader holding `ACCESS EXCLUSIVE` — retry
    `mix ecto.migrate` off-peak.
  * `CREATE SCHEMA IF NOT EXISTS "mailglass"`, then `ALTER TABLE public.<t> SET
    SCHEMA "mailglass"` for all four core tables (indexes, constraints, and
    sequences move with each table; the table comment survives the OID move).
  * the append-only immutability function does NOT move with the table (it is a
    distinct `pg_proc` object), so the migration drops and recreates it
    schema-qualified — byte-parity with the shipped fresh-install DDL, so a moved
    database is indistinguishable from a freshly-installed one.

A working `down/0` reverses the move: it returns all four tables to `public` and
restores the `public`-qualified function and trigger.

The task is idempotent — re-running it prints `unchanged <path>` and does not
emit a second migration.

    mix mailglass.upgrade.v2_schema

Options:

  * `--schema <name>` — target schema (default `mailglass`). Validated as a
    Postgres unquoted identifier before it is interpolated into the migration.

# `migration_body`

```elixir
@spec migration_body(
  String.t(),
  keyword()
) :: String.t()
```

Returns the move-migration source for `app_module` as a string.

Exposed so tests can assert the emitted body without a full filesystem run.
Accepts `:schema` (default `"mailglass"`); the value is assumed pre-validated
by `run/1` via `Mailglass.Identifier.validate!/2`.

---

*Consult [api-reference.md](api-reference.md) for complete listing*