disable pre allocate on uncommitted txn to 1.1

[zhangxu19830126]

What type of PR is this?

• API-change
• BUG
• Improvement
• Documentation
• Feature
• Test and CI
• Code Refactoring

Which issue(s) this PR fixes:

issue #15075

What this PR does / why we need it:

disable pre allocate on uncommitted txn to 1.1

[matrix-meow]

@zhangxu19830126 Thanks for your contributions!

Pull Request Review:

Title:

The title of the pull request is clear and concise, indicating the specific change being made.

Body:

The body of the pull request provides relevant information about the type of PR and the issue it fixes. It also explains the purpose of the change, which is to disable pre-allocation on uncommitted transactions.

Changes:

1. In column_cache.go:

   • A new field committed of type bool has been added to the columnCache struct.
   • The newColumnCache function now accepts a committed parameter and initializes the committed field accordingly.
   • The maybeAllocate function now checks if low and committed are both true before proceeding with allocation.

2. In column_cache_test.go:

   • The test case for newColumnCache has been updated to pass true as the committed parameter.

3. In table_cache.go:

   • The newTableCache function now accepts a committed parameter and passes it to the newColumnCache function.
   • The commit function now sets the committed flag to true for each column in the table cache.

Suggestions for Improvement:

1. Security Concern - Lack of Synchronization:

   • The addition of the committed field in the columnCache struct introduces a potential race condition. Accessing and modifying the committed field without proper synchronization can lead to data inconsistency or unexpected behavior.
   • Recommendation: Ensure proper synchronization mechanisms (e.g., mutex locks) are used when reading and writing to the committed field to prevent race conditions.

2. Code Optimization:

   • Instead of setting the committed flag individually for each column in the tableCache during commit, consider refactoring the code to handle this operation more efficiently.
   • Recommendation: Implement a method in the columnCache struct to handle the commitment status, reducing redundancy and improving code maintainability.

3. Consistency in Function Parameters:

   • In the newColumnCache function, the committed parameter is added after the Config parameter. To maintain consistency and readability, ensure that function parameters are ordered logically.
   • Recommendation: Consider reordering the parameters in the newColumnCache function for better readability and consistency.

4. Test Coverage:

   • While the test case in column_cache_test.go has been updated to reflect the changes, it is essential to ensure comprehensive test coverage for all scenarios, including edge cases and error conditions.
   • Recommendation: Expand test coverage to validate the behavior of the code under various conditions, ensuring the correctness of the implementation.

5. Documentation:

   • It would be beneficial to update the relevant documentation or comments to reflect the changes made in the code, especially regarding the new committed field and its implications.
   • Recommendation: Update the code comments or documentation to explain the purpose and usage of the committed field for better code understanding.

By addressing the security concern, optimizing the code structure, ensuring parameter consistency, enhancing test coverage, and updating documentation, the pull request can be improved in terms of reliability, efficiency, and maintainability.