txn: only wake up waiters when locks are indeed released (#7379)

[sre-bot]

cherry-pick #7379 to release-3.0

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Signed-off-by: youjiali1995 zlwgx1023@gmail.com

What problem does this PR solve?

Problem Summary:
TiKV will wake up waiters as long as it receives requests that may release locks, e.g., pessimistic_rollback, rollback, commit. If a request doesn't release locks, typically the lock doesn't exist, it needn't wake up waiters.

In TiDB, if a pessimistic DML meets write conflict, it will use pessimistic_rollback to clean up all locks it needs to lock in this DML and then retry the DML. If a transaction is waked up and there are other transactions waiting for the lock, these transactions will be waked up by pessimistic_rollback one by one. It dramatically affects performance and results in useless retry.

What is changed and how it works?

What's Changed:
Only wake up waiters when locks are indeed released and small refactor.

Related changes

• Need to cherry-pick to the release branch

Check List

Tests

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

I think existing tests are enough and I benched it using sysbench with the workload below:

con:query(CREATE TABLE wmtest(k INT PRIMARY KEY, v INT))
con:query(string.format("UPDATE wmtest SET v = v + 1 WHERE k IN (%d, 1)", sysbench.rand.uniform(2, sysbench.opt.table_size)))

master:

threads	tps	avg lat(ms)	.95 lat(ms)	.99 retry count
1	783	1.28	1.79	0
100	71	1393	2493	800
500	16	30111	72316	1457
1000	12	71181	100000	654

This PR:

threads	tps	avg lat(ms)	.95 lat(ms)	.99 retry count
100	772	129	155	1
500	724	688	787	1
1000	647	1534	1903	5

Release note

Fix the issue that needless wake-up results in useless retry and performance reduction in heavy contention workloads.

[sre-bot]

/run-all-tests

[nrc]

There's quite a lot of rebasing errors where diff markers have been left in

[nrc]

rebase error