Disagg: Reduce the number of threads created for handling disaggregated requests

[JinheLin]

What problem does this PR solve?

Issue Number: close #9334

Problem Summary:

In StorageDisaggregated, the call chain buildReadTaskForWriteNode => buildReadTaskForWriteNodeTable => buildRNReadSegmentTask will create a DynamicThreadManager in each functions.

The total number of threads used in StorageDisaggregated is about request_count * batch_cop_tasks.size() * resp.tables().size() * table.segments().size().

What is changed and how it works?

Use IOThreadPool to replace DynamicThreadManager.

If the number of tasks is greater than the number of threads, DynamicThreadManager will create new threads to handle these tasks, while IOThreadPool will make these tasks queue up.

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

Reduce the number of threads created for handling disaggregated requests

减少处理存算分离请求创建的线程数

[JinheLin]

/retest

[CalvinNeo]

lgtm

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

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

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-08-21 07:17:05.613968162 +0000 UTC m=+336220.748418283: ☑️ agreed by Lloyd-Pottiger.
• 2024-08-22 05:07:09.893567167 +0000 UTC m=+414825.028017284: ☑️ agreed by CalvinNeo.

[ti-chi-bot]

@JinheLin: Your PR was out of date, I have automatically updated it for you.

At the same time I will also trigger all tests for you:

/run-all-tests

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[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-8.1: #9346.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.5: #9685.