KVStore: Reduce the memory before and after a large txn is committed

[CalvinNeo]

What problem does this PR solve?

Issue Number: ref #9722

Problem Summary:

What is changed and how it works?

There are two ideas:

1. The first idea is to reduce the memory after a large txn is commmitted. The mechanism is introduced in Support arena.i.purge and malloc_stats_print when jemalloc is used tidb-engine-ext#402. Merged in update proxy of master to raftstore-proxy for memory purge and memory status #9721
2. The second idea is to reduce the memory before a large txn is committed. The idea is based on the observation that the DecodedLockCFValue has the size of 128 bytes. Given a txn that updates 15m rows, the memory cost is 1.8G

The idea is that we won't store the built(parsed) DecodedLockCFValue if the lock belongs to a large txn. So everytime we scan the locks of large txns, we will parse it again.

Avoid store the built DecodedLockCFValue

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

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

None

[CalvinNeo]

---

Benchmark Time CPU Iterations

parseTest 126 ns 125 ns 5612257
parseTest 129 ns 129 ns 5612257
parseTest_mean 127 ns 127 ns 2
parseTest_median 127 ns 127 ns 2
parseTest_stddev 2.56 ns 2.56 ns 2
parseTest_cv 2.01 % 2.02 % 2

[Lloyd-Pottiger]

bool withInner(std::function<bool(const Inner &)> f) const; may be better?

[CalvinNeo]

Similar, I can move it into the DecodedLockCfValue

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: JinheLin, Lloyd-Pottiger

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-12-30 02:56:27.236155449 +0000 UTC m=+319122.592159989: ☑️ agreed by Lloyd-Pottiger.
• 2024-12-30 05:41:18.201466888 +0000 UTC m=+329013.557471454: ☑️ agreed by JinheLin.