@Marvin In prefect 3, when running

prefect server start

I get this:

File "/opt/homebrew/lib/python3.10/site-packages/alembic/script/base.py", line 266, in _catch_revision_errors
    raise util.CommandError(multiple_heads) from mh
alembic.util.exc.CommandError: Multiple head revisions are present for given argument 'head'; please specify a specific target revision, '<branchname>@head' to narrow to a specific head, or 'heads' for all heads

Application startup failed. Exiting.
Server stopped!

It seems you're encountering a common problem with Alembic, which is used by Prefect for database migrations. The error indicates that there are multiple migration heads in your database schema. This usually requires specifying a particular branch or head when applying migrations. According to the Prefect 3.x documentation, you'll need to resolve these multiple head revisions by manually specifying which head to target. You can do this using Alembic commands to manage database revisions. Although the search didn’t provide a specific solution for this error, the general approach would be: 1. List all Heads: Use Alembic to list all revisions. You can try running a command like

alembic heads

to see all the current head revisions. 2. Merge the Heads: If indeed there are multiple heads, you'll need to create a merge migration that combines these heads. 3. Specify a Target Revision: When applying migrations, specify the head revision to migrate to. For more detailed guidance, you might want to look into the Alembic documentation or Prefect's guidelines on managing self-hosted servers and handling migrations, which you can find here: Prefect Self-Hosting and Migrations. If you're still stuck, don't hesitate to explore GitHub issues or community forums since someone might have faced a similar predicament and, let's face it, misery loves company. 😟