txn: support shared lock for lock wait table by you06 · Pull Request #19094 · tikv/tikv

you06 · 2025-11-07T06:42:08Z

What is changed and how it works?

Issue Number: ref #19087

What's Changed:

Handle the shared lock in the lock wait table.

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

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

cfzjywxk · 2025-11-10T06:37:15Z

src/storage/lock_manager/lock_waiting_queue.rs

+            self.mock_lock_wait_with_shared(key, start_ts, encountered_lock_ts, resumable, false)
+        }
+
+        fn mock_lock_wait_with_shared(


It is confusing to name it must lock with shared while having a shared parameter.

..._with_shared means accept a shared parameter, and such naming habit is common in the codebase.

zyguan · 2025-11-10T10:31:52Z

src/storage/txn/scheduler.rs

+            cmd.keys.iter().any(|k| k.2)
+        } else {
+            false
+        };


Could AcquirePessimisticLockResumed write shared locks?

No, AcquirePessimisticLockResumed schedulers are only created in force lock(lock_with_conflict), and all the shared locks go through normal pessimistic lock process.

tikv/src/storage/txn/commands/mod.rs

Lines 228 to 231 in 795f22b

let allow_lock_with_conflict = match req.get_wake_up_mode() {

PessimisticLockWakeUpMode::WakeUpModeNormal => false,

PessimisticLockWakeUpMode::WakeUpModeForceLock => true,

};

After the lock wait is resumed, allow_lock_with_conflict schedulers can return a woken_up_resumable_entry.

tikv/src/storage/lock_manager/lock_waiting_queue.rs

Lines 524 to 527 in 795f22b

if lock_wait_entry.parameters.allow_lock_with_conflict {

woken_up_resumable_entry = Some(lock_wait_entry);

break;

}

Then if woken_up_resumable_entry is not none, the delay_wake_up_futures will be cast into AcquirePessimisticLockResumed

tikv/src/storage/txn/scheduler.rs

Lines 1081 to 1088 in 795f22b

if !legacy_wake_up_list.is_empty() || !delay_wake_up_futures.is_empty() {

self.wake_up_legacy_pessimistic_locks(

request_source,

metadata.clone(),

legacy_wake_up_list,

delay_wake_up_futures,

);

}

ti-chi-bot · 2025-11-13T03:47:26Z

[APPROVALNOTIFIER] This PR is APPROVED

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

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ti-chi-bot · 2025-11-13T03:47:30Z

[LGTM Timeline notifier]

Timeline:

2025-11-10 06:45:10.316724621 +0000 UTC m=+684559.759754490: ☑️ agreed by cfzjywxk.
2025-11-13 03:47:29.299292291 +0000 UTC m=+933098.742322170: ☑️ agreed by zyguan.

* implement lock waiting queue Signed-off-by: you06 <you1474600@gmail.com> * donot track shared lock in deadlock detector Signed-off-by: you06 <you1474600@gmail.com> * support lock wakeup for shared lock Signed-off-by: you06 <you1474600@gmail.com> * fmt code Signed-off-by: you06 <you1474600@gmail.com> * rename param Signed-off-by: you06 <you1474600@gmail.com> * remove unused test function Signed-off-by: you06 <you1474600@gmail.com> * boxed LockWaitEntry Signed-off-by: you06 <you1474600@gmail.com> --------- Signed-off-by: you06 <you1474600@gmail.com>

you06 added 6 commits November 7, 2025 11:29

implement lock waiting queue

31c8930

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

donot track shared lock in deadlock detector

a9a99da

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

support lock wakeup for shared lock

9340c06

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

fmt code

1240a1b

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

rename param

0760b14

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

remove unused test function

05fe622

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

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/XL Denotes a PR that changes 500-999 lines, ignoring generated files. labels Nov 7, 2025

zyguan mentioned this pull request Nov 7, 2025

Support shared lock for foreign key #19087

Open

13 tasks

boxed LockWaitEntry

2d4565e

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

you06 requested review from cfzjywxk and zyguan November 10, 2025 04:55

cfzjywxk requested a review from MyonKeminta November 10, 2025 06:34

cfzjywxk approved these changes Nov 10, 2025

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ti-chi-bot bot added needs-1-more-lgtm Indicates a PR needs 1 more LGTM. approved labels Nov 10, 2025

zyguan reviewed Nov 10, 2025

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zyguan approved these changes Nov 13, 2025

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ti-chi-bot bot added lgtm and removed needs-1-more-lgtm Indicates a PR needs 1 more LGTM. labels Nov 13, 2025

you06 merged commit 03eebcd into tikv:tikv-8.5-with-shared-lock Nov 13, 2025
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txn: support shared lock for lock wait table#19094

txn: support shared lock for lock wait table#19094
you06 merged 7 commits intotikv:tikv-8.5-with-shared-lockfrom
you06:8.5-shared-lock/wait-table

you06 commented Nov 7, 2025

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cfzjywxk Nov 10, 2025

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you06 Nov 10, 2025

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you06 Nov 12, 2025 •

edited

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	let allow_lock_with_conflict = match req.get_wake_up_mode() {
	PessimisticLockWakeUpMode::WakeUpModeNormal => false,
	PessimisticLockWakeUpMode::WakeUpModeForceLock => true,
	};

	if lock_wait_entry.parameters.allow_lock_with_conflict {
	woken_up_resumable_entry = Some(lock_wait_entry);
	break;
	}

	if !legacy_wake_up_list.is_empty() \|\| !delay_wake_up_futures.is_empty() {
	self.wake_up_legacy_pessimistic_locks(
	request_source,
	metadata.clone(),
	legacy_wake_up_list,
	delay_wake_up_futures,
	);
	}

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you06 commented Nov 7, 2025

What is changed and how it works?

Related changes

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you06 Nov 12, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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ti-chi-bot bot commented Nov 13, 2025

[LGTM Timeline notifier]

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you06 Nov 12, 2025 •

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