sem: add tidb_cloud_storage_uri to SEM hidden variable list

[tangenta]

What problem does this PR solve?

Issue Number: ref #61702

Problem Summary:

In next-gen TiDB, DXF subtasks are executed in SYSTEM keyspace TiDB. The variable tidb_cloud_storage_uri should be set by the cloud control panel, instead of users.

What changed and how does it work?

• Add tidb_cloud_storage_uri to SEM hidden variable list.

Check List

Tests

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

mysql> set @@global.tidb_cloud_storage_uri = '';
ERROR 1227 (42000): Access denied; you need (at least one of) the RESTRICTED_VARIABLES_ADMIN privilege(s) for this operation

• No need to test

  • I checked and no code files have been changed.

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

[tiprow]

Hi @tangenta. Thanks for your PR.

PRs from untrusted users cannot be marked as trusted with /ok-to-test in this repo meaning untrusted PR authors can never trigger tests themselves. Collaborators can still trigger tests on the PR using /test all.

I understand the commands that are listed here.

Details

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-sigs/prow repository.

[YangKeao]

LGTM

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 74.8065%. Comparing base (0f8643f) to head (a959fd8).
⚠️ Report is 4 commits behind head on master.

Additional details and impacted files

@@               Coverage Diff                @@
##             master     #63333        +/-   ##
================================================
+ Coverage   72.7832%   74.8065%   +2.0233%     
================================================
  Files          1832       1878        +46     
  Lines        495794     504274      +8480     
================================================
+ Hits         360855     377230     +16375     
+ Misses       113010     103716      -9294     
- Partials      21929      23328      +1399     

Flag	Coverage Δ
integration	48.5726% <100.0000%> (?)
unit	72.3309% <100.0000%> (+0.0789%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
dumpling	52.8700% <ø> (ø)
parser	∅ <ø> (∅)
br	63.4309% <ø> (+16.8988%)	⬆️

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[D3Hunter]

use units.ByteSize for better visibility

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: D3Hunter, YangKeao

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Details

Needs approval from an approver in each of these files:

• OWNERS [D3Hunter,YangKeao]
• pkg/ddl/OWNERS [D3Hunter]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2025-09-02 09:17:00.669410349 +0000 UTC m=+863712.547241293: ☑️ agreed by YangKeao.
• 2025-09-02 09:58:00.193402581 +0000 UTC m=+866172.071233535: ☑️ agreed by D3Hunter.

[D3Hunter]

/hold

you can unhold youself

[D3Hunter]

/unhold

[D3Hunter]

/cherry-pick release-nextgen-20250815

[ti-chi-bot]

@D3Hunter: once the present PR merges, I will cherry-pick it on top of release-nextgen-20250815 in the new PR and assign it to you.

Details

In response to this:

/cherry-pick release-nextgen-20250815

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.

[D3Hunter]

/retest

[tiprow]

@D3Hunter: Cannot trigger testing until a trusted user reviews the PR and leaves an /ok-to-test message.

Details

In response to this:

/retest

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-sigs/prow repository.

[ti-chi-bot]

@D3Hunter: new pull request created to branch release-nextgen-20250815: #63344.

Details

In response to this:

/cherry-pick release-nextgen-20250815

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.