server: fix bug https://asktug.com/t/topic/213082/11 (#29577)

[ti-srebot]

cherry-pick #29577 to release-5.3
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/30047

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

git push git@github.com:ti-srebot/tidb.git pr/30047:release-5.3-0f86a53d419c

---

What problem does this PR solve?

Issue Number: close #29709

See also https://asktug.com/t/topic/213082/11

Problem Summary:

Too much logs about auth plugin after upgrade tidb v5.2.2
[WARN] [conn.go:698] [“failed to check the user authplugin”] [conn=599967] [error=“Failed to get user record”]

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

- Fix the bug that TiDB logs many `failed to check the user authplugin` when a user connects to TiDB.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• djshow832
• dveeden

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[ti-srebot]

/run-all-tests

[ti-srebot]

@djshow832 you're already a collaborator in bot's repo.

[guo-shaoge]

/run-check_dev

[guo-shaoge]

/run-myisql-test

[dveeden]

/run-check_dev

[guo-shaoge]

Looks like #30450 already fixed.

[ti-chi-bot]

@ti-srebot: PR needs rebase.

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 kubernetes/test-infra repository.

[dveeden]

Looks like #30450 already fixed.

Yes looks like most (if not all) of this already made it to release-5.3.

[ti-chi-bot]

This pull request is closed because its related version has closed automatic cherry-picking.
If it's still needed, you can reopen it or just regenerate it using bot,
see:

https://prow.tidb.net/command-help#cherrypick
https://book.prow.tidb.net/#/plugins/cherrypicker