Revert "fix snapshot restore with foreign key cross db"

[YANGGMM]

Reverts #16354

[matrix-meow]

@YANGGMM Thanks for your contributions!

Here are review comments for file pkg/frontend/snapshot.go:

Pull Request Review:

Title and Body:

The title "Revert 'fix snapshot restore with foreign key cross db'" and the body "

Here are review comments for file pkg/frontend/util.go:

Pull Request Review:

Title:

The title of the pull request is clear and concise, indicating that the changes are a reversion of a specific commit related to fixing snapshot restore with foreign key cross database.

Body:

The body of the pull request provides additional context by mentioning that the revert is related to a specific issue or commit number. It would be helpful to include a brief explanation of why the reversion is necessary for better understanding.

Changes in pkg/frontend/util.go:

1. Problem - Removal of KeySep Constant:

   • The removal of the KeySep constant and related splitKey function without explanation may cause confusion for developers who rely on these functions.
   • Suggestion: If the KeySep constant and splitKey function are no longer needed, it would be beneficial to add a comment explaining the reason for their removal.

2. Problem - Incomplete genKey Function:

   • The genKey function has been modified to directly return the formatted string without splitting logic, which may lead to unexpected behavior if the split functionality was previously used elsewhere.
   • Suggestion: If the split functionality is no longer required, it would be helpful to remove the unused splitKey function and add a comment explaining the change in behavior for genKey.

3. Optimization - Simplification of genKey Function:

   • The change in the genKey function from fmt.Sprintf to direct string concatenation is a minor optimization that simplifies the code.
   • Suggestion: Consider adding a comment to highlight the optimization for clarity.

4. Problem - Inconsistent Return Type in sort Function:

   • The return type of the sort function has been changed from (ans []string, err error) to (ans []string, ok bool), which may introduce confusion due to the inconsistent use of error handling.
   • Suggestion: Ensure consistency in error handling throughout the codebase. If errors are no longer used in this context, consider updating the function signature and adding a comment to explain the change.

5. Optimization - Simplification of Error Handling in sort Function:

   • The modification in the sort function to return a boolean flag instead of an error for cycle detection simplifies the logic and improves readability.
   • Suggestion: Consider adding a comment to clarify the purpose of the boolean flag and the absence of an error return.

Overall Suggestions:

• Add comments to explain the rationale behind the removal of KeySep constant and splitKey function.
• Ensure consistency in error handling across functions that involve error returns.
• Consider adding comments to highlight optimizations and changes in function behavior for better code comprehension.

By addressing the identified problems and incorporating the suggested improvements, the codebase can be enhanced in terms of clarity, maintainability, and consistency.

Here are review comments for file pkg/frontend/util_test.go:

Pull Request Review:

Title:

The title of the pull request indicates that the changes made in a previous commit are being reverted. This suggests that the changes made in the commit titled "fix snapshot restore with foreign key cross db" are being undone.

Body:

The body of the pull request simply states that it reverts a specific commit with the given reference number.

Changes in pkg/frontend/util_test.go:

1. In the TestTopsort function:
   • The return type of the sort method has been changed from (ans []string, err error) to (ans []string, ok bool).
   • The assertion for the error (err) being nil has been replaced with an assertion for ok being true.
   • Similarly, the assertions for error being nil have been replaced with assertions for ok being true or false based on the test scenario.

Feedback and Suggestions:

1. Reverting Changes:

   • Ensure that reverting the changes made in the commit "fix snapshot restore with foreign key cross db" is necessary and does not introduce new issues or regressions.

2. Error Handling:

   • The change in return type from (ans []string, err error) to (ans []string, ok bool) might not be the best approach. It's generally recommended to return an error explicitly rather than using a boolean flag for success/failure.
   • Consider reverting the return type change and handling errors in a more conventional way to provide better error messages and handling.

3. Test Assertions:

   • While changing the assertions from checking errors to checking boolean flags (ok), ensure that the tests still cover all relevant scenarios and provide meaningful feedback in case of failures.
   • Review the test cases to confirm that the changes in assertions accurately reflect the expected behavior of the sort method.

4. Code Optimization:

   • If the changes were made due to specific requirements or issues, consider documenting the reasons for the modifications in the code or in the commit message for better traceability.
   • Ensure that the changes align with the overall code quality standards and do not introduce unnecessary complexity.

5. Security Concerns:

   • No security issues were identified based on the provided diff. However, it's essential to conduct a thorough security review of the entire codebase to identify and address any potential vulnerabilities.

Overall:

The changes in the pull request seem focused on altering the return type and assertions in test cases. It's crucial to ensure that these modifications are necessary, maintain code quality, and do not introduce new issues. Consider the feedback provided to improve the quality and maintainability of the codebase.

Here are review comments for file test/distributed/cases/snapshot/snapshot_restore_table_with_fk.result:

Pull Request Review:

Title:

The title of the pull request is clear and indicates that the changes made in a previous commit are being reverted.

Body:

The body of the pull request provides a brief explanation that the commit being reverted is referenced by its number.

Changes:

1. The changes in the file test/distributed/cases/snapshot/snapshot_restore_table_with_fk.result show a diff in the snapshot information and various SQL commands related to database operations.

Feedback:

1. Reverting Changes: Reverting a commit should be done with caution. It's important to understand why the original fix was implemented and whether reverting it introduces any issues. Ensure that the reason for the revert is well-documented and justified.

2. Unnecessary Changes: The diff in the file includes a lot of unnecessary changes like dropping tables, databases, and snapshots. These changes may not be directly related to the issue being addressed. It's important to focus on relevant changes to keep the commit concise and clear.

3. Security Concerns: The diff includes dropping tables and databases which can lead to data loss if executed in a production environment. It's crucial to avoid including such destructive operations in test files or commits. Consider removing these destructive commands from the test file.

4. Optimization: To optimize the changes, focus on reverting the specific changes related to the issue being addressed. Remove any unrelated changes or commands that are not necessary for the purpose of the test case.

Suggestions:

1. Revert Carefully: Before reverting a commit, ensure that it is the correct action to take. If possible, investigate the reason for the original fix and consider alternative solutions rather than a revert.

2. Refine Test Cases: Update the test file to include only relevant changes that are necessary to validate the functionality being tested. Remove any extraneous commands that do not contribute to the test case.

3. Avoid Destructive Operations: Test files should not contain commands that can cause data loss or have destructive effects. Ensure that test cases only include operations that are safe to execute.

4. Separate Concerns: Keep each commit focused on a specific task or issue. Avoid mixing unrelated changes in a single commit to maintain clarity and ease of review.

By addressing these points, the quality and clarity of the codebase can be improved, ensuring that changes are relevant, safe, and optimized for testing purposes.

Here are review comments for file test/distributed/cases/snapshot/snapshot_restore_table_with_fk.sql:

Pull Request Review:

Title: Revert "fix snapshot restore with foreign key cross db"

Problem 1: Reverting a Fix

• Description: The pull request is reverting a previous fix for an issue related to snapshot restore with foreign key cross-database references.
• Suggestion: Before reverting a fix, it is essential to understand the reasons behind the original fix and whether reverting it will reintroduce the same issue. It would be beneficial to investigate the root cause of the problem and find a more sustainable solution rather than reverting fixes without a thorough analysis.

Problem 2: Unnecessary Code Removal

• Description: The changes in the file snapshot_restore_table_with_fk.sql involve the removal of a significant portion of code related to cross-database foreign key dependencies.
• Suggestion: Instead of simply deleting the code, consider commenting out the code or moving it to a separate file for reference. This can help in preserving the original logic and provide context for future developers.

Problem 3: Lack of Explanation

• Description: The pull request lacks a detailed explanation in the body regarding the reasons for the revert or any additional context.
• Suggestion: It is crucial to provide a clear explanation in the pull request body about why the revert is necessary, what issues it aims to address, and any potential implications of the revert. This information can help other team members understand the decision and its impact.

Security Concerns:

• No security concerns identified in the provided changes.

Optimization Suggestions:

• Consider Refactoring: If the original fix caused unintended consequences or did not fully address the issue, consider refactoring the code instead of reverting it entirely. This approach can help in improving the codebase without losing the progress made.
• Documentation: Ensure that any changes made, including reversions, are well-documented to provide clarity to other developers and maintain a comprehensive history of code modifications.

By addressing the identified problems and considering the optimization suggestions, the pull request process can be more effective in maintaining code quality and fostering collaboration within the development team.