SQLAlchemy and Alembic failures: preserve local data before changing anything

Separate three concerns

SQLAlchemy is a database toolkit. Alembic documents migration environments and revision-based upgrades.12 We recommend treating Python imports, database access and migration state as separate checks.

python -m pip show SQLAlchemy alembic

First identify whether the database belongs to ComfyUI, a node or the launcher. Preserve its application version and backup procedure. Do not share a password-bearing connection string. A copy of a live database file is not automatically a recoverable backup.

For a missing library, follow the application's dependency requirements. For an access error, inspect the target and process permissions. For a missing revision, check that application code and migration files belong together. Do not use stamp head as a replacement for executing required migrations.

This guide does not assume the database is disposable. Test the documented recovery path on a copy and confirm that existing records remain readable before testing new writes. A successful command exit alone is not evidence that user data survived correctly.

Related checks

• Keep a reproducible ComfyUI repair record without exposing secrets
• Where to run ComfyUI commands: PowerShell, CMD and virtual environments

Research draft. No local/GPU reproduction or independent editorial sign-off. Upstream statements and our recommendations are distinguished.