Prompt
Help us change the DB schema according to the goals and data below. [input] Goals and usage situations: I would like to resolve the stuck point in changing the DB schema and decide the next action. Resources to review: Existing schema and changes required Conditions and Constraints: Please proceed based on the provided data, and mark any missing facts as requiring confirmation. Previous attempts and records: This is my first attempt. Please proceed from the parts that can be confirmed in the current data. [Key points to check in this topic] Check the order of compatibility, backfill, lock, verification, and recovery. [Results to be created this time] Please write a test that verifies the actual risk among normal, error, warning, and rerun cases. Avoid expectations that just replicate the implementation, and explain the scope of control of external dependencies. Write down what failures each test catches. [Working Principle] Give priority to facts confirmed in the current environment and provided code. Don't create APIs/files/tests that don't exist. Treat sensitive values as hidden examples and leave unexecuted tasks as unexecuted. If there is no input that will change the results, ask only the necessary questions first and proceed with the parts that can be confirmed with data. [Completion criteria] Check whether the test fails if the required contract is violated and distinguish between non-execution. Distinguish between the basis for the outcome, remaining uncertainties, and next actions, and mark only what has actually been confirmed as complete.