store: change the mpp response chan size to 0

[wshwsh12]

What problem does this PR solve?

Issue Number: ref #34143

Problem Summary:
Now the chan size is 4096. If the data is too large and all data is buffered in tidb, it will make tidb OOM.

Heap:

What is changed and how it works?

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)

-- Load tpcc5000 and create tiflash replica
use tpcc5000;
set tidb_allow_mpp = on;
set tidb_enforce_mpp = on;
select * from order_line;

BenchBot Test. None means v6.4.0 patch this pr.

• 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.

None

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• XuHuaiyu
• guo-shaoge

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[wshwsh12]

/hold

[wshwsh12]

/unhold

[wuhuizuo]

/run-unit-test

[wshwsh12]

/run-unit-test

[wshwsh12]

/merge

[ti-chi-bot]

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

Commit hash: 4740664

[ti-chi-bot]

@wshwsh12: Your PR was out of date, I have automatically updated it for you.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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[hawkingrei]

/run-all-tests

[hawkingrei]

/run-all-test

[wshwsh12]

/run-all-tests