txn: implement Lock encode/decode by you06 · Pull Request #19237 · tikv/tikv

you06 · 2025-12-25T16:31:01Z

What is changed and how it works?

Issue Number: ref #19087

What's Changed:

Implemente encode/decode for shared lock.

Related changes

PR to update pingcap/docs/pingcap/docs-cn:
Need to cherry-pick to the release branch

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

Release note

None

Copilot

Pull request overview

This PR implements encode/decode functionality for shared locks in TiKV's MVCC system. The implementation adds support for a new LockType::Shared variant that can contain multiple transaction locks, enabling shared locking semantics.

Introduces SharedLocks struct to represent multiple transaction locks under a single shared lock
Updates parse_lock() to return Either<Lock, SharedLocks> to handle both lock types
Adds serialization/deserialization logic for the new shared lock format with embedded transaction info segments

Reviewed changes

Copilot reviewed 38 out of 39 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
components/txn_types/src/lock.rs	Core implementation: adds `LockType::Shared` enum variant, `SharedLocks` struct with encoding/decoding, `parse_lock()` function, and helper methods
components/txn_types/src/lib.rs	Exports new `LockOrSharedLocks` type alias and `parse_lock()` function
components/txn_types/src/write.rs	Maps `LockType::Shared` to `None` for WriteType conversion
components/tikv_util/src/lib.rs	Adds `PartialEq` derive to `Either` enum
components/tikv_util/src/memory.rs	Implements `HeapSize` for `Either` and refactors tuple `HeapSize` implementations using macro
src/storage/types.rs	Maps `LockType::Shared` to `kvrpcpb::Op::SharedLock` in MvccInfo
src/storage/txn/store.rs	Handles `Either` return type from `parse_lock()` with unimplemented for SharedLocks case
src/storage/txn/commands/*.rs	Updates lock loading sites to handle `Either<Lock, SharedLocks>` return type
src/storage/txn/actions/*.rs	Updates transaction action handlers to pattern match on Either type
src/storage/mvcc/reader/*.rs	Updates all MVCC readers and scanners to handle new lock type with Either pattern matching
src/storage/mvcc/*.rs	Updates MVCC module to handle Either return type from `load_lock()`
src/storage/mod.rs	Renames `futures::Either` to avoid conflict with `tikv_util::Either`
src/server/*.rs	Updates debug and reset_to_version modules to handle Either type
components/resolved_ts/src/*.rs	Updates resolved timestamp components to handle new lock type
components/cdc/src/*.rs	Updates CDC components to pattern match on Either type
components/backup-stream/src/*.rs	Updates backup stream to handle shared locks and Either type
components/snap_recovery/src/*.rs	Updates snapshot recovery to handle Either type
Cargo.toml	Updates kvproto dependency to specific revision with SharedLock support
Cargo.lock	Updates dependency lock with new kvproto revision

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Copilot · 2025-12-25T16:35:11Z

components/resolved_ts/src/cmd.rs

+                let lock = match txn_types::parse_lock(value).ok()? {
+                    Either::Left(lock) => lock,
+                    Either::Right(_shared_locks) => unimplemented!(
+                        "SharedLocks returned from txn_types::parse_lock is not supported here"
+                    ),
+                };
+                debug!("skip lock record";
+                    "type" => ?lock.lock_type,
+                    "start_ts" => ?lock.ts,
+                    "key" => log_wrappers::Value(key),
+                    "for_update_ts" => ?lock.for_update_ts);


In the non-matching branch (line 178-194), when debug_assertions is enabled, the code calls txn_types::parse_lock() to fully parse the lock just to extract debugging information. However, this parsing is already skipped in release builds. For consistency and efficiency, consider using Lock::detect_lock_ts() instead of full parsing to get the timestamp for the debug log, or only parse if absolutely necessary for debugging.

Suggested change

let lock = match txn_types::parse_lock(value).ok()? {

Either::Left(lock) => lock,

Either::Right(_shared_locks) => unimplemented!(

"SharedLocks returned from txn_types::parse_lock is not supported here"

),

};

debug!("skip lock record";

"type" => ?lock.lock_type,

"start_ts" => ?lock.ts,

"key" => log_wrappers::Value(key),

"for_update_ts" => ?lock.for_update_ts);

let ts = Lock::detect_lock_ts(value).ok();

debug!("skip lock record";

"type" => ?lock_type,

"start_ts" => ?ts,

"key" => log_wrappers::Value(key));

components/txn_types/src/lock.rs

Signed-off-by: you06 <you1474600@gmail.com> split Lock Signed-off-by: you06 <you1474600@gmail.com> split Lock and SharedLocks into 2 types definition Signed-off-by: you06 <you1474600@gmail.com> remove unused changes Signed-off-by: you06 <you1474600@gmail.com> fix build & clippy Signed-off-by: you06 <you1474600@gmail.com> format code Signed-off-by: you06 <you1474600@gmail.com> refactor Signed-off-by: you06 <you1474600@gmail.com> simplify code Signed-off-by: you06 <you1474600@gmail.com>

Signed-off-by: you06 <you1474600@gmail.com>

Copilot

Pull request overview

Copilot reviewed 41 out of 42 changed files in this pull request and generated 9 comments.

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components/txn_types/src/lock.rs

src/storage/txn/store.rs

components/txn_types/src/lock.rs

components/cdc/src/delegate.rs

components/txn_types/src/lock.rs

Signed-off-by: you06 <you1474600@gmail.com>

components/txn_types/src/lock.rs

Signed-off-by: you06 <you1474600@gmail.com>

zyguan

Generally LGTM

zyguan · 2026-01-05T14:07:33Z

components/txn_types/src/lock.rs

+
+#[derive(PartialEq, Clone, Debug, Default)]
+pub struct SharedLocks {
+    pub txn_info_segments: HashMap<TimeStamp, Either<Vec<u8>, Lock>>,


For those common fields (like, rollback_ts, last_chang) associated with the key, do we plan to add them when it's necessary?

I do think so, let's keep minimal change in the lock.

last_change_ts is an optimization which is not a must do.

Rollback records need to be written to write cf, so they are possible unnecessary here.

src/storage/mvcc/reader/scanner/forward.rs

Signed-off-by: you06 <you1474600@gmail.com>

you06 · 2026-01-06T06:16:05Z

/retest

ti-chi-bot · 2026-01-06T06:26:23Z

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: cfzjywxk, zyguan

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ti-chi-bot · 2026-01-06T06:26:25Z

[LGTM Timeline notifier]

Timeline:

2026-01-06 06:20:53.193974288 +0000 UTC m=+683209.012282740: ☑️ agreed by zyguan.
2026-01-06 06:26:24.39057791 +0000 UTC m=+683540.208886342: ☑️ agreed by cfzjywxk.

ref tikv#19087 Implemente encode/decode for shared lock. Signed-off-by: you06 <you1474600@gmail.com>

ref #19087 Implemente encode/decode for shared lock. Signed-off-by: you06 <you1474600@gmail.com> Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Copilot AI review requested due to automatic review settings December 25, 2025 16:31

ti-chi-bot bot added release-note-none Denotes a PR that doesn't merit a release note. dco-signoff: yes Indicates the PR's author has signed the dco. size/XXL Denotes a PR that changes 1000+ lines, ignoring generated files. labels Dec 25, 2025

Copilot started reviewing on behalf of you06 December 25, 2025 16:31 View session

you06 mentioned this pull request Dec 25, 2025

Support shared lock for foreign key #19087

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13 tasks

you06 changed the title ~~Master shared lock/lock~~ txn: implement Lock encode/decode Dec 25, 2025

Copilot AI reviewed Dec 25, 2025

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you06-pingcap force-pushed the master-shared-lock/lock branch from be7c862 to 0aa8118 Compare December 26, 2025 11:32

you06 added 3 commits December 26, 2025 21:49

remove unused functions for SharedLocks

c660134

Signed-off-by: you06 <you1474600@gmail.com>

update SharedLocks::parse

29d6abe

Signed-off-by: you06 <you1474600@gmail.com>

support SharedLocks

6ad959c

Signed-off-by: you06 <you1474600@gmail.com>

you06 requested review from cfzjywxk, Copilot and zyguan December 26, 2025 15:07

Copilot started reviewing on behalf of you06 December 26, 2025 15:07 View session

Copilot AI reviewed Dec 26, 2025

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you06 added 2 commits December 27, 2025 00:28

implement unimplements

e928f07

Signed-off-by: you06 <you1474600@gmail.com>

accept review

0f7d2a9

Signed-off-by: you06 <you1474600@gmail.com>

cfzjywxk reviewed Dec 31, 2025

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you06 added 4 commits January 5, 2026 15:08

address comment

867de19

Signed-off-by: you06 <you1474600@gmail.com>

address comment

d1626b3

Signed-off-by: you06 <you1474600@gmail.com>

comment function

3c839cc

Signed-off-by: you06 <you1474600@gmail.com>

format code

3439322

Signed-off-by: you06 <you1474600@gmail.com>

zyguan reviewed Jan 5, 2026

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address comment

0e6ecea

Signed-off-by: you06 <you1474600@gmail.com>

zyguan approved these changes Jan 6, 2026

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ti-chi-bot bot added the needs-1-more-lgtm Indicates a PR needs 1 more LGTM. label Jan 6, 2026

ti-chi-bot bot added the approved label Jan 6, 2026

cfzjywxk approved these changes Jan 6, 2026

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ti-chi-bot bot added the lgtm label Jan 6, 2026

ti-chi-bot bot removed the needs-1-more-lgtm Indicates a PR needs 1 more LGTM. label Jan 6, 2026

ti-chi-bot bot merged commit 607a79a into tikv:master Jan 6, 2026
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ti-chi-bot bot added this to the Pool milestone Jan 6, 2026

you06-pingcap pushed a commit to you06/tikv that referenced this pull request Feb 24, 2026

txn: implement Lock encode/decode (tikv#19237)

ffa02fe

ref tikv#19087 Implemente encode/decode for shared lock. Signed-off-by: you06 <you1474600@gmail.com>

you06 mentioned this pull request Feb 24, 2026

txn: implement Lock encode/decode (#19237) #19389

Merged

9 tasks

you06-pingcap pushed a commit to you06/tikv that referenced this pull request Feb 27, 2026

txn: implement Lock encode/decode (tikv#19237)

a63469e

ref tikv#19087 Implemente encode/decode for shared lock. Signed-off-by: you06 <you1474600@gmail.com>

ti-chi-bot bot pushed a commit that referenced this pull request Feb 27, 2026

txn: implement Lock encode/decode (#19237) (#19389)

281129c

ref #19087 Implemente encode/decode for shared lock. Signed-off-by: you06 <you1474600@gmail.com> Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

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you06 commented Dec 25, 2025

What is changed and how it works?

Related changes

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you06 commented Jan 6, 2026

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[LGTM Timeline notifier]

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