session: make min start ts reporter aware of internal session from get_lock()

[tangenta]

What problem does this PR solve?

Issue Number: close #38706

Problem Summary:

Before this PR, the pessimistic transaction started by get_lock() can only live several minutes:

[WARN] [2pc.go:1118] ["stop TxnHeartBeat"] [error="txn 437065830059212803 heartbeat fail, primary key = 7480000000000000435f698000000000000001016100000000000000f8, err = txn 437065830059212803 not found"]

TiDB needs to report the minimal start ts to PD regularly, in order to advance the GC savepoint. However, the reporter is not aware of the pessimistic transaction started by get_lock(). When the GC worker cleans the lock record, the above error is reported.

What is changed and how it works?

This PR makes the min start ts reporter aware of get_lock() transaction.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)

select get_lock('hello', 0);

...
[INFO] [2pc.go:1107] ["send TxnHeartBeat"] [startTS=437068143044853763] [newTTL=31000]
...
[INFO] [2pc.go:1107] ["send TxnHeartBeat"] [startTS=437068143044853763] [newTTL=2651034]

The lock could be hold for more than 40 mins.

• 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

Please refer to Release Notes Language Style Guide to write a quality release note.

Fix an issue that `get_lock()` cannot hold for more than 10 minutes.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• ekexium
• you06

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[ekexium]

If a connection is closed without releasing the lock, will there be resource leak?

[tangenta]

If a connection is closed without releasing the lock, will there be resource leak?

No. When the session closed, all the internal sessions will be returned to the pool.

tidb/session/session.go

Line 2551 in cc2a038

s.ReleaseAllAdvisoryLocks()

[ekexium]

Just curious, why not getting a session from the session pool?

[tangenta]

Just curious, why not getting a session from the session pool?

Because the variables of the session in pool is undetermined, it may cause the integration test fail. To minimize the unstable cases, it is better to use a new session like before :(

[tangenta]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 9b3e6b2

[ti-chi-bot]

In response to a cherrypick label: new pull request created: #38827.

[ti-chi-bot]

In response to a cherrypick label: new pull request created: #38828.

[sre-bot]

TiDB MergeCI notify

✅ Well Done! New fixed [1] after this pr merged.

CI Name	Result	Duration	Compare with Parent commit
idc-jenkins-ci-tidb/integration-common-test	✅ all 17 tests passed	21 min	Fixed
idc-jenkins-ci-tidb/integration-ddl-test	🟢 all 6 tests passed	28 min	Existing passed
idc-jenkins-ci/integration-cdc-test	🟢 all 38 tests passed	20 min	Existing passed
idc-jenkins-ci-tidb/common-test	🟢 all 11 tests passed	13 min	Existing passed
idc-jenkins-ci-tidb/tics-test	🟢 all 1 tests passed	5 min 34 sec	Existing passed
idc-jenkins-ci-tidb/sqllogic-test-2	🟢 all 28 tests passed	4 min 48 sec	Existing passed
idc-jenkins-ci-tidb/sqllogic-test-1	🟢 all 26 tests passed	4 min 14 sec	Existing passed
idc-jenkins-ci-tidb/mybatis-test	🟢 all 1 tests passed	3 min 13 sec	Existing passed
idc-jenkins-ci-tidb/integration-compatibility-test	🟢 all 1 tests passed	2 min 26 sec	Existing passed
idc-jenkins-ci-tidb/plugin-test	🟢 build success, plugin test success	4min	Existing passed