fix(rocksdb): fix txn conflict checker

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[MasterPtato]

• chore(agents): add graphite-commit agent for conventional commits #3394
• fix(rivetkit): only trigger onStateChange and inspector updates for actor state changes #3393
• fix(rivetkit): reject all waiters in SinglePromiseQueue #3392
• fix(rivetkit): fix hibernatable websocket last seen message index to be i64 instead of u64 #3391
• fix(rivetkit): gracefully call _onStop for actors on runner shutdown #3390
• fix(rivetkit): fix initial hibernation state always being overridden with msgIndex of -1 #3389
• fix(rivetkit): fix missing duplex in nextjs in development #3388
• chore(runner): add safeguard against duplicate sockets #3387
• chore(runner): explicitly stringify tunnel messages, commands, and events #3386
• fix(runner): do not send websocket close on tunnel shutdown since pegboard-runner takes care of this #3385
• fix(rivetkit): fix actors trying to sleep after stop started #3384
• chore(runner): rename webSocketId -> requestId #3383
• chore(runner): add explicit close reason when client runner shuts down #3382
• fix(guard): fix 1006 when client closes ws connection #3381
• chore(runner): add child logger with runner id #3380
• chore(rivetkit): remove warnings for graceful runner shtudown #3379
• fix(gateway): fix gc logic #3378
• fix: boot dupe runners #3377
• fix(rocksdb): fix txn conflict checker #3376 👈 (View in Graphite)
• main

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[claude]

Pull Request Review: fix(rocksdb): fix txn conflict checker

Summary

This PR fixes a critical bug in the transaction conflict detection logic in RocksDB's transaction conflict tracker. The main fix corrects the interval overlap check for transaction versions to properly detect all types of conflicts.

Code Quality & Best Practices ✅

Transaction Conflict Logic Fix (transaction_conflict_tracker.rs:60-62)

Original:

if txn1_start_version > txn2.start_version && txn1_start_version < txn2.commit_version

Fixed:

if txn1_start_version < txn2.commit_version && txn2.start_version < txn1_commit_version

Analysis:

• ✅ Correct Fix: The new logic properly detects interval overlap using the standard formula: (start1 < end2) && (start2 < end1)
• ✅ Bug Identified: The original code only detected cases where txn1 started during txn2's execution, missing several conflict scenarios:
  • When txn1 completely encapsulates txn2
  • When txn2 completely encapsulates txn1
  • When txn1 starts before txn2 but they overlap
• ✅ Comment Updated: The comment now accurately reflects the logic ("intersection or encapsulation")

Debug Derive Addition ✅

Adding #[derive(Debug)] to PreviousTransaction improves debuggability without any runtime cost.

Timestamp Display (signal.rs:2, 25, 34)

Changing from Local to Utc timezone:

• ✅ Consistency: Using UTC is standard practice for distributed systems
• ✅ Reproducibility: Timestamps are now consistent across different machines/timezones
• ℹ️ Note: This changes user-facing output format from local time to UTC

Test Logging (gasoline/ctx/test.rs:248)

Enabling ANSI colors (with_ansi(true)):

• ✅ Developer Experience: Improves test output readability with colored logs
• ℹ️ Minor: Pure DX improvement, no functional impact

Potential Issues

Critical Bug Fixed 🐛

The original interval overlap check had a serious logic error that could lead to:

• Undetected conflicts: Transactions that should conflict were not detected
• Data races: Concurrent transactions could violate ACID guarantees
• Correctness issues: Could result in data corruption in edge cases

The fix properly implements the standard interval overlap algorithm.

Performance Considerations ⚡

No performance impact:

• The complexity remains O(n*m) for checking conflict ranges
• The corrected condition has the same computational cost
• Debug derive has zero runtime overhead
• UTC vs Local timezone conversion has negligible difference

Security Concerns 🔒

Positive Security Impact:

• ✅ Fixing the transaction conflict detection improves data integrity
• ✅ Prevents potential race conditions that could lead to data corruption
• ✅ Strengthens ACID guarantees for concurrent transactions

No new security vulnerabilities introduced.

Test Coverage 🧪

Recommendation: This is a critical bug fix in transaction conflict detection. Consider adding:

1. Unit tests for the interval overlap logic with edge cases:

   • Txn1 completely before txn2 (no overlap)
   • Txn1 completely after txn2 (no overlap)
   • Txn1 encapsulates txn2 (overlap - now fixed)
   • Txn2 encapsulates txn1 (overlap - now fixed)
   • Partial overlaps from both directions
   • Exact version boundaries

2. Integration tests demonstrating the bug was fixed:

   • Concurrent transactions with overlapping version ranges
   • Verify conflicts are properly detected

Example test case that would have failed before:

// Txn2: versions 10-20
// Txn1: versions 5-25 (encapsulates txn2)
// Should detect conflict but old code would miss it

Additional Notes

The changes align well with the repository conventions:

• ✅ Follows Rust best practices
• ✅ Proper use of comparison operators for interval checking
• ✅ Clear, descriptive comments

Verdict

LGTM with recommendation for tests 🎯

This is a critical correctness fix that should be merged, but given the severity of the original bug, adding comprehensive test coverage would provide confidence that:

1. The fix works correctly
2. The bug doesn't regress in the future
3. All edge cases are handled

The other changes (UTC timestamps, ANSI colors, Debug derive) are all positive quality-of-life improvements.

---

Review generated with assistance from Claude Code

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commit: a81bd73

[graphite-app]

Merge activity

• Nov 6, 5:47 AM UTC: NathanFlurry added this pull request to the Graphite merge queue.
• Nov 6, 5:48 AM UTC: CI is running for this pull request on a draft pull request (#3395) due to your merge queue CI optimization settings.
• Nov 6, 5:50 AM UTC: Merged by the Graphite merge queue via draft PR: #3395.