# `mix pgflow.check_schema`
[🔗](https://github.com/agoodway/pgflow/blob/v0.7.0/lib/mix/tasks/pgflow.check_schema.ex#L1)

Verifies that the pgflow database schema exists and is compatible with
this version of the Elixir implementation.

## Usage

    mix pgflow.check_schema [options]

## Options

  * `--repo` - The Ecto repo to check. Default: reads from config
  * `--notify-trigger` - `deferred` (default) or `pgmq_default`, matching
    the app's `PgFlow.Config` `:notify_trigger` setting

## Examples

    mix pgflow.check_schema
    mix pgflow.check_schema --repo MyApp.Repo
    mix pgflow.check_schema --notify-trigger pgmq_default

## What It Checks

  1. The `pgflow` schema and required tables exist
  2. Installed core and helpers versions meet the bundled minimums
  3. Required function signatures: five-argument `start_tasks/5`,
     `ensure_flow_compiled/4`, and no obsolete three-argument claim
  4. Queue identity constraints on `step_tasks` and `steps`
  5. Eight-field `step_task_record` layout including `attempts_count`
  6. Task status enum includes `skipped` and `cancelled`
  7. pgmq extension is available

When those checks pass, it also prints warnings, without failing, for
advisory findings:

  * pgmq notify triggers on flow queues (`lower(flow_slug)`) that are not
    `DEFERRABLE INITIALLY DEFERRED`. Workers using
    `signal_strategy: :notify` recreate them deferred on boot; an immediate
    trigger makes producers hold the queue's notify throttle row lock until
    their transaction commits. `pgmq.enable_notify_insert` and pgmq
    upgrades that rebuild notify triggers (`ALTER EXTENSION pgmq UPDATE`,
    for example to 1.13.1) recreate them immediate. Pass
    `--notify-trigger pgmq_default` when the app configures
    `notify_trigger: :pgmq_default` to skip this warning.
  * Notify triggers on flow queues with no `pgmq.notify_insert_throttle`
    row. pgmq keeps that table UNLOGGED, so crash recovery and Neon compute
    restarts empty it, and a trigger without its row sends no NOTIFY until
    a worker boot or `PgFlow.Signal.Notify` restores the row.
  * Notify triggers on partitioned flow queue tables when the installed
    pgmq (before 1.13.1) cannot resolve a partition to its queue, so those
    queues never send NOTIFY.

See `docs/UPSTREAM_COMPATIBILITY.md` for the full contract.

---

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