session: make min start ts reporter aware of internal session from get_lock() (#38790)

[ti-chi-bot]

This is an automated cherry-pick of #38790

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

To complete the pull request process, please ask the reviewers in the list to review by filling /cc @reviewer in the comment.
After your PR has acquired the required number of LGTMs, you can assign this pull request to the committer in the list by filling /assign @committer in the comment to help you merge this pull request.

The full list of commands accepted by this bot can be found here.

Reviewer can indicate their review by submitting an approval review.
Reviewer can cancel approval by submitting a request changes review.

[tangenta]

/merge

[ti-chi-bot]

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

Commit hash: dde4e2e