PostgreSQL table ownership and migration failures in self-hosted Langfuse

If you encounter permission errors during PostgreSQL migrations like the following, it typically occurs when the database user running migrations has changed, as new users won’t own existing tables and therefore cannot modify them.

DbError { severity: "ERROR", code: SqlState(E42501), message: "permission denied for table projects" }

You can verify mixed ownership by checking table owners:

\dt public.*

Solutions

Option 1: Transfer table ownership

-- Replace 'new_user' with your current migration user
ALTER TABLE table_name OWNER TO new_user;

Option 2: Use dedicated migration user

Set the DIRECT_URL environment variable to use a superuser or table owner specifically for migrations:

DIRECT_URL=postgresql://migration_user:password@host:port/database

This allows Prisma to use different credentials for migrations while keeping your regular DATABASE_URL for application operations.