# `mix phoenix_kit.doctor`
[🔗](https://github.com/BeamLabEU/phoenix_kit/blob/v1.7.164/lib/mix/tasks/phoenix_kit.doctor.ex#L1)

Diagnoses PhoenixKit installation, migration, and runtime issues.

Runs a comprehensive suite of checks covering database connectivity, pool
configuration, PgBouncer detection, migration state, lock conflicts, and
application configuration. Prints a clear pass/fail report with actionable
remediation steps.

## Usage

    $ mix phoenix_kit.doctor
    $ mix phoenix_kit.doctor --prefix=auth

## Options

  * `--prefix` - Database schema prefix (default: "public")

## Checks Performed

  1. **Repo Detection** — Can we find and start the Ecto repo?
  2. **DB Connectivity** — Can we execute a simple query?
  3. **Pool Configuration** — Pool size, checkout timeout, queue settings
  4. **PgBouncer Detection** — Is PgBouncer between app and PostgreSQL?
  5. **Migration State** — PhoenixKit version (COMMENT), schema_migrations alignment
  6. **Pending Migrations** — Migration files not yet recorded in schema_migrations
  7. **UUID Column Types** — Detects varchar uuid columns that crash Ecto on startup
  8. **NULL UUIDs in FK Sources** — Detects NULL uuids that cause infinite backfill loops
  9. **Orphaned FK References** — Detects orphaned rows that block FK constraint creation
 10. **Lock Conflicts** — Any blocked or long-running queries?
 11. **Orphaned Connections** — Idle-in-transaction or stuck connections
 12. **Oban Configuration** — Queues and plugins that consume pool connections
 13. **Supervisor Children** — What's running (update_mode vs full)?
 14. **Update Mode** — Is update_mode active?

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