planner: forbid load data with empty field terminator (#36500)

[ti-srebot]

cherry-pick #36500 to release-5.4
You can switch your code base to this Pull Request by using git-extras:

# In tidb repo:
git pr https://github.com/pingcap/tidb/pull/36684

After apply modifications, you can push your change to this PR via:

git push git@github.com:ti-srebot/tidb.git pr/36684:release-5.4-bce6901705cd

---

Signed-off-by: zyguan zhongyangguan@gmail.com

What problem does this PR solve?

Issue Number: close #33298

Problem Summary: load data with empty field terminator leads to 100% CPU usage and never finishing.

What is changed and how it works?

Just forbid load data with empty field terminator for a quick fix, since we do not support fixed-row format yet.

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]

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[ti-chi-bot]

@ti-srebot: This cherry pick PR is for a release branch and has not yet been approved by release team.
Adding the do-not-merge/cherry-pick-not-approved label.

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[ti-srebot]

/run-all-tests

[ti-srebot]

@zyguan you're already a collaborator in bot's repo.

[sre-bot]

Code Coverage Details: https://codecov.io/github/pingcap/tidb/commit/9a5d5a3197912079e6f588f936423c31fcbbc039

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (release-5.4@0eeb0bb). Click here to learn what that means.
The diff coverage is n/a.

Additional details and impacted files

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