merge join result block if needed

[windtalker]

What problem does this PR solve?

Issue Number: close #6533

Problem Summary:

What is changed and how it works?

This pr is a re-implementaion of #6529, #6529 is reverted because it will make performance regression. Compared to #6529, this pr reduce the potential performance regression by

• Use a more reasonable threshold to trigger block merge
• Only merge the result blocks inside one probe block

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

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• SeaRise
• gengliqi

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[SeaRise]

Others LGTM

[SeaRise]

lgtm

[windtalker]

/merge

[ti-chi-bot]

@windtalker: It seems you want to merge this PR, I will help you trigger all the tests:

/run-all-tests

You only need to trigger /merge once, and if the CI test fails, you just re-trigger the test that failed and the bot will merge the PR for you after the CI passes.

If you have any questions about the PR merge process, please refer to pr process.

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[ti-chi-bot]

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

Commit hash: 2b70eaf

[ti-chi-bot]

@windtalker: Your PR was out of date, I have automatically updated it for you.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

trigger some heavy tests which will not run always when PR updated.

If the CI test fails, you just re-trigger the test that failed and the bot will merge the PR for you after the CI passes.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.