support bypassing shared lock

[you06]

What problem does this PR solve?

Issue Number: close #10704

Problem Summary:

What is changed and how it works?

This PR support parsing the TiKV's shared lock and bypass them in conflict check.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

None

Summary by CodeRabbit

• New Features
  • Added support for a new shared lock type in the KV store and added corresponding metric tracking.
• Tests
  • Added tests to validate detection and scanner behavior with the new shared lock.
• Chores
  • Updated a vendored submodule reference.

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[coderabbitai]

📝 Walkthrough

Walkthrough

Adds explicit support for a new Shared lock type: enum value, decoding and retrieval handling, metric tracking, test coverage, and an updated contrib/kvproto submodule reference.

Changes

Cohort / File(s)	Summary
Lock Type Definition dbms/src/Storages/KVStore/TiKVHelpers/TiKVRecordFormat.h	Added Shared = 'H' enumerator to DB::RecordKVFormat::LockType.
Lock Decoding & Retrieval dbms/src/Storages/KVStore/TiKVHelpers/DecodedLockCFValue.cpp	Recognize Shared in decodeLockCfValue (set res.lock_type = SharedLock and early return); treat SharedLock like Lock/PessimisticLock in Inner::getLockInfoPtr (returns nullptr).
Metrics dbms/src/Common/TiFlashMetrics.h	Added new sub-metric type_shared_lock_put to tiflash_raft_process_keys metric set.
Tests dbms/src/Storages/KVStore/tests/gtest_kvstore.cpp	Added test block inserting a LockType::Shared entry and asserting scanner returns no LockInfo (mirrors existing lock tests).
Submodule contrib/kvproto	Updated kvproto submodule reference from commit db74bf0e3ac1... to 6db24b6c67f3... (single-line ref update).

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Poem

🐰 I nibble code with gentle hop,
'H' arrives — a SharedLock stop,
Decoders learn the new small mark,
Metrics count it in the ark,
Tests nod softly — all is copacetic.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 16.67% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title 'support bypassing shared lock' is directly related to the main change: adding support for parsing and bypassing shared locks in conflict checks, as reflected across all modified files.
Description check	✅ Passed	The PR description follows the template with issue reference, commit message, and test checklist completed; however, the Problem Summary section is empty.
Linked Issues check	✅ Passed	The PR successfully implements support for parsing and handling TiKV's shared locks as required by #10704, with proper enum additions, parsing logic, metrics tracking, and unit test coverage.
Out of Scope Changes check	✅ Passed	All changes are in scope: enum/metric additions for shared lock support, parsing logic in DecodedLockCFValue, submodule update for kvproto, and unit tests—all directly supporting the shared lock feature.

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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[you06]

/release

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: CalvinNeo, gengliqi

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Details

Needs approval from an approver in each of these files:

• OWNERS [CalvinNeo,gengliqi]

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2026-02-05 08:04:20.833979341 +0000 UTC m=+340531.935378054: ☑️ agreed by gengliqi.
• 2026-02-06 03:17:50.799147216 +0000 UTC m=+409741.900545936: ☑️ agreed by CalvinNeo.