executor: Lower the log level from info to debug for index merge reader

[yibin87]

What problem does this PR solve?

Issue Number: close #41949

Problem Summary:

What is changed and how it works?

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

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:

• hawkingrei
• wshwsh12

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[yibin87]

/cc @XuHuaiyu @wshwsh12

[hawkingrei]

/merge

[ti-chi-bot]

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

Commit hash: 255afd5

[yibin87]

/run-check_dev_2

[yibin87]

/run-all-tests

[yibin87]

/test check-dev2

[yibin87]

/test unit-test

[dveeden]

The checklist in the PR description says there is a unit test, but I don't see any. I think this is only tested manually, which I think is ok for this PR.

However I do think a release note for this would be good to help users figure out in which version this is fixed when deciding to upgrade etc.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.5: #42607.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.1: #42838.