ddl: add COMMENTS column to DDL jobs and enhance job reorg meta handling (#57392)

[ti-chi-bot]

This is an automated cherry-pick of #57392

What problem does this PR solve?

Issue Number: ref https://github.com/pingcap/tidb/issues/57229 #57526

Problem Summary: See #57229

What changed and how does it work?

• Add COMMENTS column to ADMIN SHOW DDL JOBS.
• Refine DDL job reorg meta initialization. For example, let "modify column"/"reorg partition" and other reorg DDL types utilize ReorgMeta.Concurrency and ReorgMeta.BatchSize.

Check List

Tests

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

• [x] 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.

add COMMENTS column to ADMIN SHOW DDL JOBS

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 85.62500% with 23 lines in your changes missing coverage. Please review.

Please upload report for BASE (release-8.5@9862e83). Learn more about missing BASE report.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## release-8.5 #57595 +/- ## ================================================ Coverage ? 56.9561% ================================================ Files ? 1770 Lines ? 626357 Branches ? 0 ================================================ Hits ? 356749 Misses ? 245455 Partials ? 24153 ``` | [Flag](https://app.codecov.io/gh/pingcap/tidb/pull/57595/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | Coverage Δ | | |---|---|---| | [integration](https://app.codecov.io/gh/pingcap/tidb/pull/57595/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | `36.9042% <63.1250%> (?)` | | | [unit](https://app.codecov.io/gh/pingcap/tidb/pull/57595/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | `72.5944% <79.3750%> (?)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap#carryforward-flags-in-the-pull-request-comment) to find out more. | [Components](https://app.codecov.io/gh/pingcap/tidb/pull/57595/components?src=pr&el=components&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | Coverage Δ | | |---|---|---| | [dumpling](https://app.codecov.io/gh/pingcap/tidb/pull/57595/components?src=pr&el=component&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | `52.9478% <0.0000%> (?)` | | | [parser](https://app.codecov.io/gh/pingcap/tidb/pull/57595/components?src=pr&el=component&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | `∅ <0.0000%> (?)` | | | [br](https://app.codecov.io/gh/pingcap/tidb/pull/57595/components?src=pr&el=component&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pingcap) | `52.2873% <0.0000%> (?)` | |

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[ti-chi-bot[bot]]

[LGTM Timeline notifier]

Timeline:

• 2024-11-21 09:53:29.346992306 +0000 UTC m=+111796.966646809: :ballot_box_with_check: agreed by tangenta.
• 2024-11-21 10:26:43.28710708 +0000 UTC m=+113790.906761597: :ballot_box_with_check: agreed by hawkingrei.

[tangenta]

/retest

[ti-chi-bot[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: hawkingrei, tangenta, YuJuncen

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

The pull request process is described here

Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/pingcap/tidb/blob/release-8.5/OWNERS)~~ [YuJuncen,hawkingrei,tangenta] - ~~[br/OWNERS](https://github.com/pingcap/tidb/blob/release-8.5/br/OWNERS)~~ [YuJuncen] - ~~[pkg/ddl/OWNERS](https://github.com/pingcap/tidb/blob/release-8.5/pkg/ddl/OWNERS)~~ [tangenta] - ~~[pkg/meta/OWNERS](https://github.com/pingcap/tidb/blob/release-8.5/pkg/meta/OWNERS)~~ [tangenta] - ~~[pkg/planner/OWNERS](https://github.com/pingcap/tidb/blob/release-8.5/pkg/planner/OWNERS)~~ [hawkingrei] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment