Introduce TransactionContext in Consensus Commit

[brfrn169]

Description

This PR refactors Consensus Commit by introducing the TransactionContext class, which centralizes transaction state management and improves code readability. One of the benefits of this change is that it also makes CrudHandler stateless.

Related issues and/or PRs

N/A

Changes made

• Introduced TransactionContext
• Updated the Consensus Commit code to use it.

Checklist

The following is a best-effort checklist. If any items in this checklist are not applicable to this PR or are dependent on other, unmerged PRs, please still mark the checkboxes after you have read and understood each item.

• I have commented my code, particularly in hard-to-understand areas.
• I have updated the documentation to reflect the changes.
• I have considered whether similar issues could occur in other products, components, or modules if this PR is for bug fixes.
• Any remaining open issues linked to this PR are documented and up-to-date (Jira, GitHub, etc.).
• Tests (unit, integration, etc.) have been added for the changes.
• My changes generate no new warnings.
• Any dependent changes in other PRs have been merged and published.

Additional notes (optional)

N/A

Release notes

N/A

[Copilot]

Pull Request Overview

This PR introduces the TransactionContext class to consolidate transaction-related state and context information, refactoring the Consensus Commit implementation. The purpose is to improve code organization by centralizing transaction metadata and reducing parameter passing of the Snapshot object throughout the codebase.

• Introduces TransactionContext class containing transaction ID, snapshot, isolation level, read-only flag, one-operation flag, scanners, and recovery results
• Refactors method signatures across consensus commit classes to accept TransactionContext instead of multiple individual parameters or Snapshot
• Updates test classes to create and use TransactionContext instances instead of relying on snapshot-based operations

Reviewed Changes

Copilot reviewed 22 out of 22 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
TransactionContext.java	New class consolidating transaction state and behavior methods
TwoPhaseConsensusCommit.java	Updated to use TransactionContext for all operations
ConsensusCommit.java	Refactored to work with TransactionContext instead of direct snapshot access
CrudHandler.java	Modified to accept TransactionContext parameter in all methods
CommitHandler.java	Updated method signatures to use TransactionContext
Multiple test files	Updated to create and use TransactionContext in test scenarios

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[gemini-code-assist]

Summary of Changes

Hello @brfrn169, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request introduces a TransactionContext class to refactor the Consensus Commit transaction components. This new class centralizes transaction-specific state and metadata, simplifying method signatures and improving modularity across CommitHandler, CrudHandler, ConsensusCommit, and TwoPhaseConsensusCommit classes. The changes involve updating numerous method parameters from individual Snapshot objects and flags to the unified TransactionContext object, and adjusting internal logic to access transaction details through this new context. Corresponding test files have been updated to align with these API modifications.

Highlights

• Intent: This pull request refactors the Consensus Commit transaction logic by introducing a new TransactionContext class. This class centralizes transaction-related information such as the transaction ID, snapshot, isolation level, read-only status, one-operation mode, and lists of open scanners and recovery results. This change aims to simplify method signatures and improve the overall structure of the transaction components.
• Changes: The core change involves replacing direct Snapshot object parameters and individual boolean flags (like readOnly) with a single TransactionContext object across various classes.

Specifically:

• A new TransactionContext.java file is added, encapsulating transaction metadata and state (ID, snapshot, isolation, read-only/one-operation flags, scanners, recovery results).
• CommitHandler.java and CommitHandlerWithGroupCommit.java are updated to accept TransactionContext in their commit-related methods, accessing transaction details through this new object.
• ConsensusCommit.java and TwoPhaseConsensusCommit.java now hold an instance of TransactionContext and delegate calls to it or pass it to CrudHandler and CommitHandler methods.
• ConsensusCommitManager.java and TwoPhaseConsensusCommitManager.java are modified to create and manage the CrudHandler and TransactionContext instances, passing them to the transaction objects.
• CrudHandler.java is significantly refactored: it no longer stores transaction-specific state (like Snapshot, readOnly, scanners, recoveryResults) but receives TransactionContext in its methods. Its constructor is simplified, and internal helper methods are updated to use the context.
• MutationConditionsValidator.java is updated to receive TransactionContext to retrieve the transaction ID for exception messages.
• Snapshot.java removes methods that are now handled by TransactionContext (e.g., getId, getIsolation, isValidationRequired).
• All relevant test files have been updated to reflect these API changes, ensuring compatibility and correctness with the new TransactionContext abstraction.

• Reviewer Activity: No reviewer activity was provided in the pull request description.

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[gemini-code-assist]

Code Review

This is a great refactoring that introduces the TransactionContext class to encapsulate transaction-specific state. This change significantly improves the design by making handlers like CrudHandler and CommitHandler stateless and reusable across transactions. The changes are applied consistently throughout the codebase.

I have a couple of suggestions to further improve the code:

• Encapsulation in TransactionContext: The new TransactionContext class exposes mutable lists as public fields. I've suggested making them private and providing controlled access to improve encapsulation and maintainability.
• Testing Object Sharing: Some tests verifying the lifecycle and sharing of CrudHandler instances were removed. I've recommended adding new tests to verify the new object sharing semantics after this refactoring.

Overall, this is a high-quality pull request that improves the codebase's structure.

[brfrn169]

/gemini review

[Copilot]

Pull Request Overview

Copilot reviewed 23 out of 23 changed files in this pull request and generated no new comments.

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[gemini-code-assist]

Code Review

This is a great refactoring that introduces TransactionContext to encapsulate transaction-related state. The changes are well-implemented and consistent across the codebase, significantly improving code clarity and maintainability. The handlers (CrudHandler, CommitHandler) are now nicely stateless with respect to individual transactions. The test suite has also been updated thoroughly to reflect these changes. I have no major concerns.

[brfrn169]

Introduced TransactionContext, which encapsulates transaction-related state.

[brfrn169]

By using TransactionContext, we can make CrudHandler stateless.

[komamitsu]

LGTM! 👍

[brfrn169]

@komamitsu Sorry, I made an additional change in bf5ac7c. Could you please take a look at it? 🙇