Disable the coordinator write omission in ScalarDB #203
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Summary of Changes
Hello @jnmt, 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 addresses a critical issue in ScalarDL's recovery process by ensuring that the 'coordinator write omission' optimization in ScalarDB is always disabled. This prevents read-only transactions from incorrectly appearing as 'aborted' due to the omission of coordinator state writes, thereby maintaining data consistency and correct recovery behavior for ScalarDL users.
Highlights
- Configuration Enforcement: I've added logic within
LedgerConfig.javato explicitly disable thecoordinator write omissionoptimization if it's found to be enabled. This is crucial for ScalarDL's recovery process, ensuring that the coordinator state is always written, even for read-only transactions. A warning message will be logged if the option is detected as enabled and subsequently disabled. - Test Coverage: I've introduced two new unit tests in
LedgerConfigTest.javato verify the behavior of thecoordinator write omissionsetting. One test confirms that the option remains disabled if explicitly configured as such, and another confirms that the new logic correctly forces the option to be disabled even if it was initially set totrue.
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Pull Request Overview
This PR disables the coordinator write omission optimization in ScalarDB for ScalarDL to prevent read-only transactions from appearing as "aborted" when they should show as successfully committed. ScalarDL requires coordinator state information for recovery processes even for read-only transactions.
- Adds validation logic to disable coordinator write omission when enabled
- Implements warning logging when the optimization is forcibly disabled
- Adds comprehensive test coverage for both enabled and disabled scenarios
Reviewed Changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.
| File | Description |
|---|---|
| LedgerConfig.java | Adds validation logic to disable coordinator write omission and log warning |
| LedgerConfigTest.java | Adds test cases to verify proper handling of coordinator write omission settings |
Comments suppressed due to low confidence (3)
ledger/src/main/java/com/scalar/dl/ledger/config/LedgerConfig.java:525
- [nitpick] The warning message could be clearer about what action was taken. Consider changing to '...has been disabled because...' to clearly indicate the system took action to disable it.
+ " is disabled because the Coordinator write is always necessary for ScalarDL");
ledger/src/test/java/com/scalar/dl/ledger/config/LedgerConfigTest.java:586
- [nitpick] The test method name 'constructor_ConsensusCommitWithCoordinatorWriteOmissionDisabledSpecified_ShouldConstructProperly' is very long and could be shortened to improve readability. Consider 'constructor_CoordinatorWriteOmissionDisabled_ShouldConstructProperly'.
public void
ledger/src/test/java/com/scalar/dl/ledger/config/LedgerConfigTest.java:603
- [nitpick] The test method name 'constructor_ConsensusCommitWithCoordinatorWriteOmissionEnabledSpecified_ShouldConstructProperlyWithDisablingIt' is excessively long. Consider 'constructor_CoordinatorWriteOmissionEnabled_ShouldDisableItAutomatically' for better readability.
public void
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Code Review
This pull request disables the coordinator write omission optimization to ensure the recovery process in ScalarDL functions as expected. The logic is sound, and the accompanying tests effectively validate the new behavior. The feedback focuses on enhancing the warning log message for better clarity.
ledger/src/main/java/com/scalar/dl/ledger/config/LedgerConfig.java
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ledger/src/main/java/com/scalar/dl/ledger/config/LedgerConfig.java
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…java [skip ci] Co-authored-by: Josh Wong <joshua.wong@scalar-labs.com>
Description
This PR disables the coordinator write omission optimization in ScalarDB because, in ScalarDL, we use the coordinator state for the recovery process even for read-only transactions. Without disabling it, users may see the incorrect "aborted" state for read-only transactions, even if they are successfully committed.
Related issues and/or PRs
Changes made
Checklist
Additional notes (optional)
N/A
Release notes
Disabled the coordinator write omission in ScalarDB.